Give latest+qualifier inputs (e.g. latest-ea) a targeted error

Inputs like 'latest-ea' had their '-ea' suffix stripped and fell through
to the generic SemVer validation, failing with a confusing "'latest' is
not valid SemVer" message even though 'latest' is supported. Add an
explicit guard so any 'latest*' value other than exactly 'latest' throws
a targeted error explaining that 'latest' resolves GA releases only and
cannot be combined with '-ea' or other qualifiers.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

.eslintignore

@@ -1,6 +0,0 @@
-# Ignore list
-/*
-
-# Do not ignore these folders:
-!__tests__/
-!src/

.eslintrc.js

@@ -1,51 +0,0 @@
-// This is a reusable configuration file copied from https://github.com/actions/reusable-workflows/tree/main/reusable-configurations. Please don't make changes to this file as it's the subject of an automatic update.
-module.exports = {
-  extends: [
-    'eslint:recommended',
-    'plugin:@typescript-eslint/recommended',
-    'plugin:eslint-plugin-jest/recommended',
-    'eslint-config-prettier'
-  ],
-  parser: '@typescript-eslint/parser',
-  plugins: ['@typescript-eslint', 'eslint-plugin-node', 'eslint-plugin-jest'],
-  rules: {
-    '@typescript-eslint/no-require-imports': 'error',
-    '@typescript-eslint/no-non-null-assertion': 'off',
-    '@typescript-eslint/no-explicit-any': 'off',
-    '@typescript-eslint/no-empty-function': 'off',
-    '@typescript-eslint/ban-ts-comment': [
-      'error',
-      {
-        'ts-ignore': 'allow-with-description'
-      }
-    ],
-    'no-console': 'error',
-    'yoda': 'error',
-    'prefer-const': [
-      'error',
-      {
-        destructuring: 'all'
-      }
-    ],
-    'no-control-regex': 'off',
-    'no-constant-condition': ['error', {checkLoops: false}],
-    'node/no-extraneous-import': 'error'
-  },
-  overrides: [
-    {
-      files: ['**/*{test,spec}.ts'],
-      rules: {
-        '@typescript-eslint/no-unused-vars': 'off',
-        'jest/no-standalone-expect': 'off',
-        'jest/no-conditional-expect': 'off',
-        'no-console': 'off',
-
-      }
-    }
-  ],
-  env: {
-    node: true,
-    es6: true,
-    'jest/globals': true
-  }
-};

.licensed.yml

@@ -10,8 +10,11 @@ allowed:
   - mit
   - cc0-1.0
   - unlicense
+  - blueoak-1.0.0
 
 reviewed:
   npm:
     - "@actions/http-client" # MIT (license text present), but detected as "other"
-    - "argparse" # Python Software Foundation License (PSF), but detected as "other"
+    - "argparse" # Python Software Foundation License (PSF), but detected as "other"
+    - "balanced-match"
+    - "brace-expansion"

.licenses/npm/@actions/cache.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@actions/cache"
-version: 5.1.0
+version: 6.1.0
 type: npm
 summary: Actions cache lib
 homepage: https://github.com/actions/toolkit/tree/main/packages/cache

.licenses/npm/@actions/core.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@actions/core"
-version: 2.0.3
+version: 3.0.1
 type: npm
 summary: Actions core lib
 homepage: https://github.com/actions/toolkit/tree/main/packages/core

.licenses/npm/@actions/exec.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@actions/exec"
-version: 2.0.0
+version: 3.0.0
 type: npm
 summary: Actions exec lib
 homepage: https://github.com/actions/toolkit/tree/main/packages/exec

.licenses/npm/@actions/glob-0.6.1.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@actions/glob"
-version: 0.5.1
+version: 0.6.1
 type: npm
 summary: Actions glob lib
 homepage: https://github.com/actions/toolkit/tree/main/packages/glob

.licenses/npm/@actions/glob-0.7.0.dep.yml

@@ -0,0 +1,20 @@
+---
+name: "@actions/glob"
+version: 0.7.0
+type: npm
+summary: Actions glob lib
+homepage: https://github.com/actions/toolkit/tree/main/packages/glob
+license: mit
+licenses:
+- sources: LICENSE.md
+  text: |-
+    The MIT License (MIT)
+
+    Copyright 2019 GitHub
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+notices: []

.licenses/npm/@actions/http-client.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@actions/http-client"
-version: 3.0.2
+version: 4.0.1
 type: npm
 summary: Actions Http Client
 homepage: https://github.com/actions/toolkit/tree/main/packages/http-client

.licenses/npm/@actions/io.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@actions/io"
-version: 2.0.0
+version: 3.0.2
 type: npm
 summary: Actions io lib
 homepage: https://github.com/actions/toolkit/tree/main/packages/io

.licenses/npm/@actions/tool-cache.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@actions/tool-cache"
-version: 3.0.1
+version: 4.0.0
 type: npm
 summary: Actions tool-cache lib
 homepage: https://github.com/actions/toolkit/tree/main/packages/tool-cache

.licenses/npm/@azure/core-client.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@azure/core-client"
-version: 1.10.1
+version: 1.10.2
 type: npm
 summary: Core library for interfacing with AutoRest generated code
 homepage: https://github.com/Azure/azure-sdk-for-js/blob/main/sdk/core/core-client/

.licenses/npm/@azure/core-http-compat.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@azure/core-http-compat"
-version: 2.3.1
+version: 2.4.0
 type: npm
 summary: Core HTTP Compatibility Library to bridge the gap between Core V1 & V2 packages.
 homepage: https://github.com/Azure/azure-sdk-for-js/blob/main/sdk/core/core-compat/

.licenses/npm/@azure/core-rest-pipeline.dep.yml

@@ -1,9 +1,9 @@
 ---
 name: "@azure/core-rest-pipeline"
-version: 1.22.2
+version: 1.24.0
 type: npm
 summary: Isomorphic client library for making HTTP requests in node.js and browser.
-homepage: https://github.com/Azure/azure-sdk-for-js/blob/main/sdk/core/core-rest-pipeline/
+homepage: https://github.com/Azure/azure-sdk-for-js/tree/main/sdk/core/core-rest-pipeline/README.md
 license: mit
 licenses:
 - sources: LICENSE

.licenses/npm/@azure/core-xml.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: "@azure/core-xml"
-version: 1.5.0
+version: 1.5.1
 type: npm
 summary: Core library for interacting with XML payloads
 homepage: https://github.com/Azure/azure-sdk-for-js/blob/main/sdk/core/core-xml/

.licenses/npm/@azure/storage-blob.dep.yml

@@ -1,9 +1,9 @@
 ---
 name: "@azure/storage-blob"
-version: 12.29.1
+version: 12.33.0
 type: npm
 summary: Microsoft Azure Storage SDK for JavaScript - Blob
-homepage: https://github.com/Azure/azure-sdk-for-js/blob/main/sdk/storage/storage-blob/
+homepage: https://github.com/Azure/azure-sdk-for-js/tree/main/sdk/storage/storage-blob/README.md
 license: mit
 licenses:
 - sources: LICENSE

.licenses/npm/@azure/storage-common.dep.yml

@@ -1,9 +1,9 @@
 ---
 name: "@azure/storage-common"
-version: 12.1.1
+version: 12.4.1
 type: npm
 summary: Azure Storage Common Client Library for JavaScript
-homepage: https://github.com/Azure/azure-sdk-for-js/blob/main/sdk/storage/storage-internal-avro/
+homepage: https://github.com/Azure/azure-sdk-for-js/tree/main/sdk/storage/storage-common/README.md
 license: mit
 licenses:
 - sources: LICENSE

.licenses/npm/@typespec/ts-http-runtime.dep.yml

@@ -1,9 +1,9 @@
 ---
 name: "@typespec/ts-http-runtime"
-version: 0.3.2
+version: 0.3.6
 type: npm
 summary: Isomorphic client library for making HTTP requests in node.js and browser.
-homepage: https://github.com/Azure/azure-sdk-for-js/blob/main/sdk/core/ts-http-runtime/
+homepage: https://github.com/Azure/azure-sdk-for-js/tree/main/sdk/core/ts-http-runtime/README.md
 license: mit
 licenses:
 - sources: LICENSE

.licenses/npm/anynum.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: anynum
-version: 1.0.0
+version: 1.0.1
 type: npm
 summary: Normalize all Unicode decimal digits (Devanagari, Arabic, Thai, etc.) to
   ASCII numerals. Zero dependencies, performance-first.
@@ -30,4 +30,6 @@ licenses:
     LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     SOFTWARE.
+- sources: README.md
+  text: MIT
 notices: []

.licenses/npm/balanced-match-4.0.4.dep.yml

@@ -0,0 +1,34 @@
+---
+name: balanced-match
+version: 4.0.4
+type: npm
+summary: Match balanced character pairs, like "{" and "}"
+homepage:
+license: other
+licenses:
+- sources: LICENSE.md
+  text: |
+    (MIT)
+
+    Original code Copyright Julian Gruber <julian@juliangruber.com>
+
+    Port to TypeScript Copyright Isaac Z. Schlueter <i@izs.me>
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy of
+    this software and associated documentation files (the "Software"), to deal in
+    the Software without restriction, including without limitation the rights to
+    use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+    of the Software, and to permit persons to whom the Software is furnished to do
+    so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+notices: []

.licenses/npm/brace-expansion-1.1.15.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: brace-expansion
-version: 1.1.13
+version: 1.1.15
 type: npm
 summary: Brace expansion as known from sh/bash
 homepage: https://github.com/juliangruber/brace-expansion

.licenses/npm/brace-expansion-5.0.7.dep.yml

@@ -0,0 +1,34 @@
+---
+name: brace-expansion
+version: 5.0.7
+type: npm
+summary: Brace expansion as known from sh/bash
+homepage:
+license: other
+licenses:
+- sources: LICENSE
+  text: |
+    MIT License
+
+    Copyright Julian Gruber <julian@juliangruber.com>
+
+    TypeScript port Copyright Isaac Z. Schlueter <i@izs.me>
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+notices: []

.licenses/npm/fast-xml-builder.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: fast-xml-builder
-version: 1.2.0
+version: 1.2.1
 type: npm
 summary: Build XML from JSON without C/C++ based libraries
 homepage:

.licenses/npm/fast-xml-parser.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: fast-xml-parser
-version: 5.8.0
+version: 5.9.3
 type: npm
 summary: Validate XML, Parse XML, Build XML without C/C++ based libraries
 homepage:

.licenses/npm/is-unsafe.dep.yml

@@ -1,16 +1,17 @@
 ---
-name: "@azure/abort-controller"
+name: is-unsafe
-version: 1.1.0
+version: 1.0.1
 type: npm
-summary: Microsoft Azure SDK for JavaScript - Aborter
+summary: Zero-dependency, DOM-free, pure predicate for detecting unsafe strings across
-homepage: https://github.com/Azure/azure-sdk-for-js/tree/main/sdk/core/abort-controller/README.md
+  HTML, XML, SVG, SQL, SHELL, and REGEX contexts
+homepage:
 license: mit
 licenses:
 - sources: LICENSE
   text: |
-    The MIT License (MIT)
+    MIT License
 
-    Copyright (c) 2020 Microsoft
+    Copyright (c) 2026 Natural Intelligence
 
     Permission is hereby granted, free of charge, to any person obtaining a copy
     of this software and associated documentation files (the "Software"), to deal
@@ -29,4 +30,6 @@ licenses:
     LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     SOFTWARE.
+- sources: README.md
+  text: MIT
 notices: []

.licenses/npm/js-yaml.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: js-yaml
-version: 4.1.1
+version: 4.3.0
 type: npm
 summary: YAML 1.2 parser and serializer
 homepage:

.licenses/npm/minimatch-10.2.5.dep.yml

@@ -0,0 +1,66 @@
+---
+name: minimatch
+version: 10.2.5
+type: npm
+summary: a glob matcher in javascript
+homepage:
+license: blueoak-1.0.0
+licenses:
+- sources: LICENSE.md
+  text: |
+    # Blue Oak Model License
+
+    Version 1.0.0
+
+    ## Purpose
+
+    This license gives everyone as much permission to work with
+    this software as possible, while protecting contributors
+    from liability.
+
+    ## Acceptance
+
+    In order to receive this license, you must agree to its
+    rules. The rules of this license are both obligations
+    under that agreement and conditions to your license.
+    You must not do anything with this software that triggers
+    a rule that you cannot or will not follow.
+
+    ## Copyright
+
+    Each contributor licenses you to do everything with this
+    software that would otherwise infringe that contributor's
+    copyright in it.
+
+    ## Notices
+
+    You must ensure that everyone who gets a copy of
+    any part of this software from you, with or without
+    changes, also gets the text of this license or a link to
+    <https://blueoakcouncil.org/license/1.0.0>.
+
+    ## Excuse
+
+    If anyone notifies you in writing that you have not
+    complied with [Notices](#notices), you can keep your
+    license by taking all practical steps to comply within 30
+    days after the notice. If you do not do so, your license
+    ends immediately.
+
+    ## Patent
+
+    Each contributor licenses you to do everything with this
+    software that would otherwise infringe any patent claims
+    they can license or become able to license.
+
+    ## Reliability
+
+    No contributor can revoke this license.
+
+    ## No Liability
+
+    **_As far as the law allows, this software comes as is,
+    without any warranty or condition, and no contributor
+    will be liable to anyone for any damages related to this
+    software or this license, under any kind of legal claim._**
+notices: []

.licenses/npm/path-expression-matcher.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: path-expression-matcher
-version: 1.5.0
+version: 1.6.1
 type: npm
 summary: Efficient path tracking and pattern matching for XML/JSON parsers
 homepage: https://github.com/NaturalIntelligence/path-expression-matcher#readme

.licenses/npm/semver-6.3.1.dep.yml

@@ -1,26 +0,0 @@
----
-name: semver
-version: 6.3.1
-type: npm
-summary: The semantic version parser used by npm.
-homepage: 
-license: isc
-licenses:
-- sources: LICENSE
-  text: |
-    The ISC License
-
-    Copyright (c) Isaac Z. Schlueter and Contributors
-
-    Permission to use, copy, modify, and/or distribute this software for any
-    purpose with or without fee is hereby granted, provided that the above
-    copyright notice and this permission notice appear in all copies.
-
-    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
-    IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-notices: []

.licenses/npm/semver.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: semver
-version: 7.8.4
+version: 7.8.5
 type: npm
 summary: The semantic version parser used by npm.
 homepage:

.licenses/npm/strnum.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: strnum
-version: 2.4.0
+version: 2.4.1
 type: npm
 summary: Parse String to Number based on configuration
 homepage:

.prettierrc.js

@@ -1,11 +0,0 @@
-// This is a reusable configuration file copied from https://github.com/actions/reusable-workflows/tree/main/reusable-configurations. Please don't make changes to this file as it's the subject of an automatic update.
-module.exports = {
-  printWidth: 80,
-  tabWidth: 2,
-  useTabs: false,
-  semi: true,
-  singleQuote: true,
-  trailingComma: 'none',
-  bracketSpacing: false,
-  arrowParens: 'avoid'
-};

.prettierrc.json

@@ -0,0 +1,10 @@
+{
+  "printWidth": 80,
+  "tabWidth": 2,
+  "useTabs": false,
+  "semi": true,
+  "singleQuote": true,
+  "trailingComma": "none",
+  "bracketSpacing": false,
+  "arrowParens": "avoid"
+}

README.md

@@ -18,6 +18,10 @@ The `setup-java` action provides the following functionality for GitHub Actions
 
 This action allows you to work with Java and Scala projects.
 
+## What's new in V6
+
+- **Migrated to ESM** to enable support for the latest `@actions/*` package versions. This is an internal implementation change only. No changes are required to your workflow configuration, and the action's behavior is unchanged. Existing workflows continue to work as before.
+
 ## Breaking changes in V5
 
 - Upgraded action from node20 to node24
@@ -100,7 +104,16 @@ steps:
 The `java-version` input supports an exact version or a version range using [SemVer](https://semver.org/) notation. The values below are examples, not an exhaustive list:
 - major versions, such as: `8`, `11`, `16`, `17`, `21`, `25`
 - more specific versions: `8.0.282+8`, `8.0.232`, `11.0`, `11.0.4`, `17.0`
+- multi-field Java versions (JEP 322), such as: `11.0.9.1`, `18.0.1.1`
 - early access (EA) versions: `15-ea`, `15.0.0-ea`
+- the `latest` alias, which floats to the newest available stable (GA) release
+
+> [!NOTE]
+> - `latest` always resolves the newest version from the distribution's remote metadata (it behaves like `check-latest: true`), so it ignores any older version already present in the runner tool cache. This has the same performance trade-off described in [Check latest](#check-latest).
+> - `latest` is only supported through the `java-version` input, not through `java-version-file`, and it resolves stable (GA) releases only — it cannot be combined with `-ea`.
+> - The `jdkfile` distribution does not support `latest`, as it installs from a local file.
+> - For `oracle` and `graalvm` (Oracle GraalVM), `latest` uses the Adoptium API only to determine the newest GA **major version number** — the JDK binary itself is still downloaded from the Oracle / GraalVM servers for that major. Because these distributions have no endpoint to list their own releases, if their servers haven't published the resolved major yet, the action fails and asks you to specify a concrete version. Note the Oracle JDK license caveat below still applies to a floating `latest`.
+> - For `graalvm-community`, `latest` floats to the newest GA release published on GitHub, so it never depends on the Adoptium API and always resolves to the newest major that GraalVM Community actually ships.
 
 #### Supported distributions
 Currently, the following distributions are supported:
@@ -185,6 +198,13 @@ steps:
   run: mvn -B package --file pom.xml
 ```
 
+> [!NOTE]
+> Maven resolves plugin dependencies lazily, so a cache created by a "thin" goal
+> (e.g. `mvn compile`) can be missing plugin dependencies that later
+> `test`/`verify`/`package` jobs then re-download on every run. See
+> [Ensuring the Maven cache is complete](docs/advanced-usage.md#ensuring-the-maven-cache-is-complete-plugin-dependencies)
+> for how to seed a complete cache.
+
 #### Caching sbt dependencies
 ```yaml
 steps:

__tests__/auth.test.ts

@@ -1,24 +1,63 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import {fileURLToPath} from 'url';
 import * as io from '@actions/io';
-import * as core from '@actions/core';
 import * as fs from 'fs';
 import * as path from 'path';
 import os from 'os';
 
-import * as auth from '../src/auth';
+// Mock @actions/core before importing source modules that depend on it
-import {M2_DIR, MVN_SETTINGS_FILE} from '../src/constants';
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
 
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const auth = await import('../src/auth.js');
+const {M2_DIR, MVN_SETTINGS_FILE} = await import('../src/constants.js');
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 const m2Dir = path.join(__dirname, M2_DIR);
 const settingsFile = path.join(m2Dir, MVN_SETTINGS_FILE);
 
 describe('auth tests', () => {
-  let spyOSHomedir: jest.SpyInstance;
+  let spyOSHomedir: any;
-  let spyInfo: jest.SpyInstance;
+  let spyInfo: any;
 
   beforeEach(async () => {
     await io.rmRF(m2Dir);
     spyOSHomedir = jest.spyOn(os, 'homedir');
     spyOSHomedir.mockReturnValue(__dirname);
-    spyInfo = jest.spyOn(core, 'info');
+    spyInfo = core.info as jest.Mock;
     spyInfo.mockImplementation(() => null);
   }, 300000);
 

__tests__/cache.test.ts

@@ -1,23 +1,84 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
 import {mkdtempSync} from 'fs';
 import {tmpdir} from 'os';
 import {join} from 'path';
-import {restore, save} from '../src/cache';
 import * as fs from 'fs';
 import * as os from 'os';
-import * as core from '@actions/core';
+
-import * as cache from '@actions/cache';
+// Mock @actions/core before importing source modules that depend on it
-import * as glob from '@actions/glob';
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+jest.unstable_mockModule('@actions/cache', () => ({
+  restoreCache: jest.fn(),
+  saveCache: jest.fn(),
+  isFeatureAvailable: jest.fn(),
+  ValidationError: class ValidationError extends Error {
+    constructor(message: string) {
+      super(message);
+      this.name = 'ValidationError';
+    }
+  },
+  ReserveCacheError: class ReserveCacheError extends Error {
+    constructor(message: string) {
+      super(message);
+      this.name = 'ReserveCacheError';
+    }
+  }
+}));
+
+jest.unstable_mockModule('@actions/glob', () => ({
+  hashFiles: jest.fn(),
+  create: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const cache = await import('@actions/cache');
+const glob = await import('@actions/glob');
+const {restore, save} = await import('../src/cache.js');
 
 describe('dependency cache', () => {
   const ORIGINAL_RUNNER_OS = process.env['RUNNER_OS'];
   const ORIGINAL_GITHUB_WORKSPACE = process.env['GITHUB_WORKSPACE'];
   const ORIGINAL_CWD = process.cwd();
   let workspace: string;
-  let spyInfo: jest.SpyInstance<void, Parameters<typeof core.info>>;
+  let spyInfo: any;
-  let spyWarning: jest.SpyInstance<void, Parameters<typeof core.warning>>;
+  let spyWarning: any;
-  let spyDebug: jest.SpyInstance<void, Parameters<typeof core.debug>>;
+  let spyDebug: any;
-  let spySaveState: jest.SpyInstance<void, Parameters<typeof core.saveState>>;
+  let spySaveState: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     workspace = mkdtempSync(join(tmpdir(), 'setup-java-cache-'));
@@ -41,20 +102,20 @@ describe('dependency cache', () => {
   });
 
   beforeEach(() => {
-    spyInfo = jest.spyOn(core, 'info');
+    spyInfo = core.info as jest.Mock;
     spyInfo.mockImplementation(() => null);
 
-    spyWarning = jest.spyOn(core, 'warning');
+    spyWarning = core.warning as jest.Mock;
     spyWarning.mockImplementation(() => null);
 
-    spyDebug = jest.spyOn(core, 'debug');
+    spyDebug = core.debug as jest.Mock;
     spyDebug.mockImplementation(() => null);
 
-    spySaveState = jest.spyOn(core, 'saveState');
+    spySaveState = core.saveState as jest.Mock;
     spySaveState.mockImplementation(() => null);
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -70,27 +131,18 @@ describe('dependency cache', () => {
   });
 
   describe('restore', () => {
-    let spyCacheRestore: jest.SpyInstance<
+    let spyCacheRestore: any;
-      ReturnType<typeof cache.restoreCache>,
+    let spyGlobHashFiles: any;
-      Parameters<typeof cache.restoreCache>
+    let spySetOutput: any;
-    >;
-    let spyGlobHashFiles: jest.SpyInstance<
-      ReturnType<typeof glob.hashFiles>,
-      Parameters<typeof glob.hashFiles>
-    >;
-    let spySetOutput: jest.SpyInstance<
-      ReturnType<typeof core.setOutput>,
-      Parameters<typeof core.setOutput>
-    >;
 
     beforeEach(() => {
-      spyCacheRestore = jest
+      spyCacheRestore = (cache.restoreCache as any).mockImplementation(
-        .spyOn(cache, 'restoreCache')
+        (paths: string[], primaryKey: string) => Promise.resolve(undefined)
-        .mockImplementation((paths: string[], primaryKey: string) =>
+      );
-          Promise.resolve(undefined)
+      spyGlobHashFiles = glob.hashFiles as jest.Mock;
-        );
+      spyGlobHashFiles.mockResolvedValue('hash-stub');
-      spyGlobHashFiles = jest.spyOn(glob, 'hashFiles');
+      spySetOutput = core.setOutput as jest.Mock;
-      spySetOutput = jest.spyOn(core, 'setOutput').mockImplementation(() => {});
+      spySetOutput.mockImplementation(() => null);
       spyWarning.mockImplementation(() => null);
     });
 
@@ -102,6 +154,7 @@ describe('dependency cache', () => {
 
     describe('for maven', () => {
       it('throws error if no pom.xml, maven-wrapper.properties, or extensions.xml found', async () => {
+        spyGlobHashFiles.mockResolvedValue('');
         await expect(restore('maven', '')).rejects.toThrow(
           `No file in ${projectRoot(
             workspace
@@ -176,6 +229,7 @@ describe('dependency cache', () => {
     });
     describe('for gradle', () => {
       it('throws error if no build.gradle found', async () => {
+        spyGlobHashFiles.mockResolvedValue('');
         await expect(restore('gradle', '')).rejects.toThrow(
           `No file in ${projectRoot(
             workspace
@@ -231,6 +285,7 @@ describe('dependency cache', () => {
     });
     describe('for sbt', () => {
       it('throws error if no build.sbt found', async () => {
+        spyGlobHashFiles.mockResolvedValue('');
         await expect(restore('sbt', '')).rejects.toThrow(
           `No file in ${projectRoot(
             workspace
@@ -249,6 +304,13 @@ describe('dependency cache', () => {
         expect(spyInfo).toHaveBeenCalledWith('sbt cache is not found');
       });
       it('detects scala and sbt changes under **/project/ folder', async () => {
+        let callCount = 0;
+        spyGlobHashFiles.mockImplementation(async () => {
+          callCount++;
+          // Return same hash for first two calls, different for third
+          return callCount <= 2 ? 'hash-v1' : 'hash-v2';
+        });
+
         createFile(join(workspace, 'build.sbt'));
         createDirectory(join(workspace, 'project'));
         createFile(join(workspace, 'project/DependenciesV1.scala'));
@@ -284,6 +346,7 @@ describe('dependency cache', () => {
     });
     describe('cache-dependency-path', () => {
       it('throws error if no matching dependency file found', async () => {
+        spyGlobHashFiles.mockResolvedValue('');
         createFile(join(workspace, 'build.gradle.kts'));
         await expect(
           restore('gradle', 'sub-project/**/build.gradle.kts')
@@ -325,17 +388,12 @@ describe('dependency cache', () => {
     });
   });
   describe('save', () => {
-    let spyCacheSave: jest.SpyInstance<
+    let spyCacheSave: any;
-      ReturnType<typeof cache.saveCache>,
-      Parameters<typeof cache.saveCache>
-    >;
 
     beforeEach(() => {
-      spyCacheSave = jest
+      spyCacheSave = (cache.saveCache as any).mockImplementation(
-        .spyOn(cache, 'saveCache')
+        (paths: string[], key: string) => Promise.resolve(0)
-        .mockImplementation((paths: string[], key: string) =>
+      );
-          Promise.resolve(0)
-        );
       spyWarning.mockImplementation(() => null);
     });
 
@@ -495,14 +553,14 @@ describe('dependency cache', () => {
 });
 
 function resetState() {
-  jest.spyOn(core, 'getState').mockReset();
+  (core.getState as jest.Mock).mockReset();
 }
 
 /**
  * Create states to emulate a restore process without build file.
  */
 function createStateForMissingBuildFile() {
-  jest.spyOn(core, 'getState').mockImplementation(name => {
+  (core.getState as jest.Mock<any>).mockImplementation((name: any) => {
     switch (name) {
       case 'cache-primary-key':
         return 'setup-java-cache-';
@@ -516,7 +574,7 @@ function createStateForMissingBuildFile() {
  * Create states to emulate a successful restore process.
  */
 function createStateForSuccessfulRestore() {
-  jest.spyOn(core, 'getState').mockImplementation(name => {
+  (core.getState as jest.Mock<any>).mockImplementation((name: any) => {
     switch (name) {
       case 'cache-primary-key':
         return 'setup-java-cache-primary-key';

__tests__/cleanup-java.test.ts

@@ -1,32 +1,87 @@
-import {run as cleanup} from '../src/cleanup-java';
+import {
-import * as core from '@actions/core';
+  jest,
-import * as cache from '@actions/cache';
+  describe,
-import * as util from '../src/util';
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+
+// Mock @actions/cache before importing source modules
+const real_cache_module = await import('@actions/cache');
+jest.unstable_mockModule('@actions/cache', () => ({
+  ...real_cache_module,
+  saveCache: jest.fn(),
+  restoreCache: jest.fn()
+}));
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const real_util_module = await import('../src/util.js');
+jest.unstable_mockModule('../src/util.js', () => ({
+  ...real_util_module,
+  extractJdkFile: jest.fn(),
+  getDownloadArchiveExtension: jest.fn(),
+  getToolcachePath: jest.fn(),
+  isJobStatusSuccess: jest.fn(),
+  renameWinArchive: jest.fn(),
+  isVersionSatisfies: real_util_module.isVersionSatisfies,
+  getTempDir: real_util_module.getTempDir
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const cache = await import('@actions/cache');
+const {run: cleanup} = await import('../src/cleanup-java.js');
+const util = await import('../src/util.js');
 
 describe('cleanup', () => {
-  let spyWarning: jest.SpyInstance<void, Parameters<typeof core.warning>>;
+  let spyWarning: any;
-  let spyInfo: jest.SpyInstance<void, Parameters<typeof core.info>>;
+  let spyInfo: any;
-  let spyCacheSave: jest.SpyInstance<
+  let spyCacheSave: any;
-    ReturnType<typeof cache.saveCache>,
+  let spyJobStatusSuccess: any;
-    Parameters<typeof cache.saveCache>
+  let spyCoreError: any;
-  >;
-  let spyJobStatusSuccess: jest.SpyInstance;
-  let spyCoreError: jest.SpyInstance;
 
   beforeEach(() => {
-    spyWarning = jest.spyOn(core, 'warning');
+    spyWarning = core.warning as jest.Mock;
     spyWarning.mockImplementation(() => null);
 
-    spyInfo = jest.spyOn(core, 'info');
+    spyInfo = core.info as jest.Mock;
     spyInfo.mockImplementation(() => null);
 
-    spyCacheSave = jest.spyOn(cache, 'saveCache');
+    spyCacheSave = cache.saveCache as jest.Mock;
 
-    spyJobStatusSuccess = jest.spyOn(util, 'isJobStatusSuccess');
+    spyJobStatusSuccess = util.isJobStatusSuccess as jest.Mock;
     spyJobStatusSuccess.mockReturnValue(true);
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
 
     createStateForSuccessfulRestore();
@@ -47,7 +102,7 @@ describe('cleanup', () => {
         )
       )
     );
-    jest.spyOn(core, 'getInput').mockImplementation((name: string) => {
+    (core.getInput as jest.Mock<any>).mockImplementation((name: string) => {
       return name === 'cache' ? 'gradle' : '';
     });
     await cleanup();
@@ -59,7 +114,7 @@ describe('cleanup', () => {
     spyCacheSave.mockImplementation((paths: string[], key: string) =>
       Promise.reject(new Error('Unexpected error'))
     );
-    jest.spyOn(core, 'getInput').mockImplementation((name: string) => {
+    (core.getInput as jest.Mock<any>).mockImplementation((name: string) => {
       return name === 'cache' ? 'gradle' : '';
     });
     await cleanup();
@@ -68,14 +123,14 @@ describe('cleanup', () => {
 });
 
 function resetState() {
-  jest.spyOn(core, 'getState').mockReset();
+  (core.getState as jest.Mock).mockReset();
 }
 
 /**
  * Create states to emulate a successful restore process.
  */
 function createStateForSuccessfulRestore() {
-  jest.spyOn(core, 'getState').mockImplementation(name => {
+  (core.getState as jest.Mock<any>).mockImplementation((name: any) => {
     switch (name) {
       case 'cache-primary-key':
         return 'setup-java-cache-primary-key';

__tests__/distributors/adopt-installer.test.ts

@@ -1,21 +1,59 @@
-import {HttpClient} from '@actions/http-client';
-import {IAdoptAvailableVersions} from '../../src/distributions/adopt/models';
 import {
-  AdoptDistribution,
+  jest,
-  AdoptImplementation
+  describe,
-} from '../../src/distributions/adopt/installer';
+  it,
-import {TemurinDistribution} from '../../src/distributions/temurin/installer';
+  expect,
-import {JavaInstallerOptions} from '../../src/distributions/base-models';
+  beforeEach,
-
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import {HttpClient} from '@actions/http-client';
 import os from 'os';
 
-import manifestData from '../data/adopt.json';
+import manifestData from '../data/adopt.json' with {type: 'json'};
-import * as core from '@actions/core';
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {AdoptDistribution, AdoptImplementation} =
+  await import('../../src/distributions/adopt/installer.js');
+const {TemurinDistribution} =
+  await import('../../src/distributions/temurin/installer.js');
+
+import type {IAdoptAvailableVersions} from '../../src/distributions/adopt/models.js';
+import type {AdoptImplementation as AdoptImplementationType} from '../../src/distributions/adopt/installer.js';
+import type {JavaInstallerOptions} from '../../src/distributions/base-models.js';
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
-  let spyCoreWarning: jest.SpyInstance;
+  let spyCoreWarning: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -26,9 +64,9 @@ describe('getAvailableVersions', () => {
     });
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
-    spyCoreWarning = jest.spyOn(core, 'warning');
+    spyCoreWarning = core.warning as jest.Mock;
     spyCoreWarning.mockImplementation(() => {});
   });
 
@@ -123,7 +161,7 @@ describe('getAvailableVersions', () => {
     'build correct url for %s',
     async (
       installerOptions: JavaInstallerOptions,
-      impl: AdoptImplementation,
+      impl: AdoptImplementationType,
       expectedParameters
     ) => {
       const distribution = new AdoptDistribution(installerOptions, impl);
@@ -204,7 +242,7 @@ describe('getAvailableVersions', () => {
     [AdoptImplementation.OpenJ9, 'jre', 'Java_Adopt-OpenJ9_jre']
   ])(
     'find right toolchain folder',
-    (impl: AdoptImplementation, packageType: string, expected: string) => {
+    (impl: AdoptImplementationType, packageType: string, expected: string) => {
       const distribution = new AdoptDistribution(
         {
           version: '11',
@@ -263,11 +301,11 @@ describe('findPackageForDownload', () => {
       url: 'https://example.test/temurin-11.tar.gz'
     };
     const temurinFindPackageForDownload = jest
-      .fn()
+      .fn<any>()
       .mockResolvedValue(temurinRelease);
     const temurinDistribution = {
       findPackageForDownload: temurinFindPackageForDownload
-    } as unknown as TemurinDistribution;
+    } as any;
 
     const distribution = new AdoptDistribution(
       {
@@ -279,7 +317,7 @@ describe('findPackageForDownload', () => {
       AdoptImplementation.Hotspot,
       temurinDistribution
     );
-    const adoptLookupSpy = jest.fn();
+    const adoptLookupSpy = jest.fn<any>();
     distribution['getAvailableVersions'] = adoptLookupSpy;
 
     const resolvedVersion = await distribution['findPackageForDownload']('11');

__tests__/distributors/base-installer.test.ts

@@ -1,19 +1,90 @@
-import * as tc from '@actions/tool-cache';
+import {
-import * as core from '@actions/core';
+  jest,
-import * as util from '../../src/util';
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {
+  JavaDownloadRelease,
+  JavaInstallerOptions,
+  JavaInstallerResults
+} from '../../src/distributions/base-models.js';
 
 import path from 'path';
 import * as semver from 'semver';
 
-import {JavaBase} from '../../src/distributions/base-installer';
-import {
-  JavaDownloadRelease,
-  JavaInstallerOptions,
-  JavaInstallerResults
-} from '../../src/distributions/base-models';
-
 import os from 'os';
 
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+jest.unstable_mockModule('@actions/tool-cache', () => ({
+  find: jest.fn(),
+  findAllVersions: jest.fn(),
+  downloadTool: jest.fn(),
+  extractZip: jest.fn(),
+  extractTar: jest.fn(),
+  extract7z: jest.fn(),
+  extractXar: jest.fn(),
+  cacheDir: jest.fn(),
+  cacheFile: jest.fn(),
+  getManifestFromRepo: jest.fn(),
+  findFromManifest: jest.fn(),
+  evaluateVersions: jest.fn(),
+  HTTPError: class HTTPError extends Error {
+    httpStatusCode: number;
+    constructor(statusCode: number) {
+      super(`HTTP Error: ${statusCode}`);
+      this.httpStatusCode = statusCode;
+    }
+  }
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  extractJdkFile: jest.fn(),
+  getDownloadArchiveExtension: jest.fn(),
+  getToolcachePath: jest.fn(),
+  isJobStatusSuccess: jest.fn(),
+  renameWinArchive: jest.fn(),
+  isVersionSatisfies: real_util_module.isVersionSatisfies,
+  getTempDir: real_util_module.getTempDir
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const tc = await import('@actions/tool-cache');
+const util = await import('../../src/util.js');
+const {JavaBase} = await import('../../src/distributions/base-installer.js');
+
 class EmptyJavaBase extends JavaBase {
   constructor(installerOptions: JavaInstallerOptions) {
     super('Empty', installerOptions);
@@ -53,12 +124,12 @@ describe('findInToolcache', () => {
   const javaPath = path.join('Java_Empty_jdk', actualJavaVersion, 'x64');
 
   let mockJavaBase: EmptyJavaBase;
-  let spyGetToolcachePath: jest.SpyInstance;
+  let spyGetToolcachePath: any;
-  let spyTcFindAllVersions: jest.SpyInstance;
+  let spyTcFindAllVersions: any;
 
   beforeEach(() => {
-    spyGetToolcachePath = jest.spyOn(util, 'getToolcachePath');
+    spyGetToolcachePath = util.getToolcachePath as jest.Mock;
-    spyTcFindAllVersions = jest.spyOn(tc, 'findAllVersions');
+    spyTcFindAllVersions = tc.findAllVersions as jest.Mock;
   });
 
   afterEach(() => {
@@ -241,17 +312,17 @@ describe('setupJava', () => {
 
   let mockJavaBase: EmptyJavaBase;
 
-  let spyGetToolcachePath: jest.SpyInstance;
+  let spyGetToolcachePath: any;
-  let spyTcFindAllVersions: jest.SpyInstance;
+  let spyTcFindAllVersions: any;
-  let spyCoreDebug: jest.SpyInstance;
+  let spyCoreDebug: any;
-  let spyCoreInfo: jest.SpyInstance;
+  let spyCoreInfo: any;
-  let spyCoreExportVariable: jest.SpyInstance;
+  let spyCoreExportVariable: any;
-  let spyCoreAddPath: jest.SpyInstance;
+  let spyCoreAddPath: any;
-  let spyCoreSetOutput: jest.SpyInstance;
+  let spyCoreSetOutput: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
-    spyGetToolcachePath = jest.spyOn(util, 'getToolcachePath');
+    spyGetToolcachePath = util.getToolcachePath as jest.Mock;
     spyGetToolcachePath.mockImplementation(
       (toolname: string, javaVersion: string, architecture: string) => {
         const semverVersion = new semver.Range(javaVersion);
@@ -269,27 +340,27 @@ describe('setupJava', () => {
       }
     );
 
-    spyTcFindAllVersions = jest.spyOn(tc, 'findAllVersions');
+    spyTcFindAllVersions = tc.findAllVersions as jest.Mock;
     spyTcFindAllVersions.mockReturnValue([installedJavaVersion]);
 
     // Spy on core methods
-    spyCoreDebug = jest.spyOn(core, 'debug');
+    spyCoreDebug = core.debug as jest.Mock;
     spyCoreDebug.mockImplementation(() => undefined);
 
-    spyCoreInfo = jest.spyOn(core, 'info');
+    spyCoreInfo = core.info as jest.Mock;
     spyCoreInfo.mockImplementation(() => undefined);
 
-    spyCoreAddPath = jest.spyOn(core, 'addPath');
+    spyCoreAddPath = core.addPath as jest.Mock;
     spyCoreAddPath.mockImplementation(() => undefined);
 
-    spyCoreExportVariable = jest.spyOn(core, 'exportVariable');
+    spyCoreExportVariable = core.exportVariable as jest.Mock;
     spyCoreExportVariable.mockImplementation(() => undefined);
 
-    spyCoreSetOutput = jest.spyOn(core, 'setOutput');
+    spyCoreSetOutput = core.setOutput as jest.Mock;
     spyCoreSetOutput.mockImplementation(() => undefined);
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => undefined);
 
     jest.spyOn(os, 'arch').mockReturnValue('x86' as ReturnType<typeof os.arch>);
@@ -349,6 +420,29 @@ describe('setupJava', () => {
     expect(spyCoreInfo).not.toHaveBeenCalledWith('Trying to download...');
   });
 
+  it('should resolve the latest version from remote when java-version is "latest", even if a version is cached', async () => {
+    mockJavaBase = new EmptyJavaBase({
+      version: 'latest',
+      architecture: 'x86',
+      packageType: 'jdk',
+      checkLatest: false
+    });
+
+    await expect(mockJavaBase.setupJava()).resolves.toEqual({
+      version: actualJavaVersion,
+      path: javaPathInstalled
+    });
+
+    // `latest` must bypass the tool-cache short-circuit and always resolve remotely
+    expect(spyCoreInfo).toHaveBeenCalledWith(
+      'Trying to resolve the latest version from remote'
+    );
+    expect(spyCoreInfo).toHaveBeenCalledWith('Trying to download...');
+    expect(spyCoreInfo).not.toHaveBeenCalledWith(
+      `Resolved Java ${installedJavaVersion} from tool-cache`
+    );
+  });
+
   it.each([
     [
       {
@@ -673,11 +767,18 @@ describe('normalizeVersion', () => {
   const DummyJavaBase = JavaBase as any;
 
   it.each([
-    ['11', {version: '11', stable: true}],
+    ['11', {version: '11', stable: true, latest: false}],
-    ['11.0', {version: '11.0', stable: true}],
+    ['11.0', {version: '11.0', stable: true, latest: false}],
-    ['11.0.10', {version: '11.0.10', stable: true}],
+    ['11.0.10', {version: '11.0.10', stable: true, latest: false}],
-    ['11-ea', {version: '11', stable: false}],
+    ['11-ea', {version: '11', stable: false, latest: false}],
-    ['11.0.2-ea', {version: '11.0.2', stable: false}]
+    ['11.0.2-ea', {version: '11.0.2', stable: false, latest: false}],
+    ['18.0.1.1', {version: '18.0.1+1', stable: true, latest: false}],
+    ['11.0.9.1', {version: '11.0.9+1', stable: true, latest: false}],
+    ['12.0.2.1.0', {version: '12.0.2+1.0', stable: true, latest: false}],
+    ['18.0.1.1-ea', {version: '18.0.1+1', stable: false, latest: false}],
+    ['latest', {version: 'x', stable: true, latest: true}],
+    ['LATEST', {version: 'x', stable: true, latest: true}],
+    ['  Latest  ', {version: 'x', stable: true, latest: true}]
   ])('normalizeVersion from %s to %s', (input, expected) => {
     expect(DummyJavaBase.prototype.normalizeVersion.call(null, input)).toEqual(
       expected
@@ -692,6 +793,17 @@ describe('normalizeVersion', () => {
       `The string '${version}' is not valid SemVer notation for a Java version. Please check README file for code snippets and more detailed information`
     );
   });
+
+  it.each(['latest-ea', 'latest.1', 'LATEST-EA', '  latest-ea  '])(
+    'normalizeVersion should throw a targeted error for latest combined with a qualifier (%s)',
+    version => {
+      expect(
+        DummyJavaBase.prototype.normalizeVersion.bind(null, version)
+      ).toThrow(
+        `The 'latest' alias resolves stable (GA) releases only and cannot be combined with '-ea' or other qualifiers (received '${version}'). Use 'latest' on its own, or specify a concrete version.`
+      );
+    }
+  );
 });
 
 describe('createVersionNotFoundError', () => {

__tests__/distributors/corretto-installer.test.ts

@@ -1,17 +1,62 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {JavaInstallerOptions} from '../../src/distributions/base-models.js';
 import {HttpClient} from '@actions/http-client';
-import {JavaInstallerOptions} from '../../src/distributions/base-models';
 
-import {CorrettoDistribution} from '../../src/distributions/corretto/installer';
-import * as util from '../../src/util';
 import os from 'os';
-import * as core from '@actions/core';
 
-import manifestData from '../data/corretto.json';
+import manifestData from '../data/corretto.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  getDownloadArchiveExtension: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {CorrettoDistribution} =
+  await import('../../src/distributions/corretto/installer.js');
+const util = await import('../../src/util.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: ReturnType<typeof jest.spyOn>;
-  let spyGetDownloadArchiveExtension: jest.SpyInstance;
+  let spyGetDownloadArchiveExtension: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -20,13 +65,11 @@ describe('getAvailableVersions', () => {
       headers: {},
       result: manifestData
     });
-    spyGetDownloadArchiveExtension = jest.spyOn(
+    spyGetDownloadArchiveExtension =
-      util,
+      util.getDownloadArchiveExtension as jest.Mock;
-      'getDownloadArchiveExtension'
-    );
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -161,6 +204,24 @@ describe('getAvailableVersions', () => {
       expect(availableVersion.url).toBe(expectedLink);
     });
 
+    it('with latest resolves to the newest available major version', async () => {
+      const distribution = new CorrettoDistribution({
+        version: 'latest',
+        architecture: 'x64',
+        packageType: 'jdk',
+        checkLatest: false
+      });
+      mockPlatform(distribution, 'linux');
+
+      const availableVersion =
+        await distribution['findPackageForDownload']('x');
+      expect(availableVersion).not.toBeNull();
+      // 18 is the newest major present in the mocked Corretto index
+      expect(availableVersion.url).toBe(
+        'https://corretto.aws/downloads/resources/18.0.0.37.1/amazon-corretto-18.0.0.37.1-linux-x64.tar.gz'
+      );
+    });
+
     it('with unstable version expect to throw not supported error', async () => {
       const version = '18.0.1-ea';
       const distribution = new CorrettoDistribution({
@@ -235,7 +296,7 @@ describe('getAvailableVersions', () => {
   });
 
   const mockPlatform = (
-    distribution: CorrettoDistribution,
+    distribution: InstanceType<typeof CorrettoDistribution>,
     platform: string
   ) => {
     distribution['getPlatformOption'] = () => platform;

__tests__/distributors/dragonwell-installer.test.ts

@@ -1,14 +1,59 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
 import {HttpClient} from '@actions/http-client';
-import {DragonwellDistribution} from '../../src/distributions/dragonwell/installer';
-import * as utils from '../../src/util';
-import * as core from '@actions/core';
 
-import manifestData from '../data/dragonwell.json';
+import manifestData from '../data/dragonwell.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  getDownloadArchiveExtension: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {DragonwellDistribution} =
+  await import('../../src/distributions/dragonwell/installer.js');
+const utils = await import('../../src/util.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyUtilGetDownloadArchiveExtension: jest.SpyInstance;
+  let spyUtilGetDownloadArchiveExtension: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -18,14 +63,12 @@ describe('getAvailableVersions', () => {
       result: manifestData
     });
 
-    spyUtilGetDownloadArchiveExtension = jest.spyOn(
+    spyUtilGetDownloadArchiveExtension =
-      utils,
+      utils.getDownloadArchiveExtension as jest.Mock;
-      'getDownloadArchiveExtension'
-    );
     spyUtilGetDownloadArchiveExtension.mockReturnValue('tar.gz');
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -36,7 +79,7 @@ describe('getAvailableVersions', () => {
   });
 
   const mockPlatform = (
-    distribution: DragonwellDistribution,
+    distribution: InstanceType<typeof DragonwellDistribution>,
     platform: string
   ) => {
     distribution['getPlatformOption'] = () => platform;

__tests__/distributors/graalvm-installer.test.ts

@@ -1,53 +1,116 @@
-import * as core from '@actions/core';
-import * as tc from '@actions/tool-cache';
-import * as http from '@actions/http-client';
-import fs from 'fs';
-import path from 'path';
 import {
-  GraalVMCommunityDistribution,
+  jest,
-  GraalVMDistribution
+  describe,
-} from '../../src/distributions/graalvm/installer';
+  it,
-import {getJavaDistribution} from '../../src/distributions/distribution-factory';
+  expect,
-import {JavaInstallerOptions} from '../../src/distributions/base-models';
+  beforeEach,
-import * as util from '../../src/util';
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import path from 'path';
 
-jest.mock('@actions/core');
+// Mock @actions modules
-jest.mock('@actions/tool-cache');
+jest.unstable_mockModule('@actions/core', () => ({
-jest.mock('@actions/http-client');
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
 
-jest.mock('../../src/util', () => ({
+jest.unstable_mockModule('@actions/tool-cache', () => ({
-  ...jest.requireActual('../../src/util'),
+  find: jest.fn(),
+  findAllVersions: jest.fn(),
+  downloadTool: jest.fn(),
+  extractZip: jest.fn(),
+  extractTar: jest.fn(),
+  extract7z: jest.fn(),
+  extractXar: jest.fn(),
+  cacheDir: jest.fn(),
+  cacheFile: jest.fn(),
+  getManifestFromRepo: jest.fn(),
+  findFromManifest: jest.fn(),
+  evaluateVersions: jest.fn()
+}));
+
+jest.unstable_mockModule('@actions/http-client', () => ({
+  HttpClient: jest.fn().mockImplementation(() => ({
+    getJson: jest.fn(),
+    head: jest.fn(),
+    get: jest.fn()
+  })),
+  HttpClientError: class HttpClientError extends Error {
+    statusCode: number;
+    constructor(message: string, statusCode: number) {
+      super(message);
+      this.statusCode = statusCode;
+    }
+  },
+  HttpCodes: {OK: 200, NotFound: 404, Unauthorized: 401, Forbidden: 403}
+}));
+
+// Get real util first, then mock specific functions
+const realUtil = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...realUtil,
   extractJdkFile: jest.fn(),
   getDownloadArchiveExtension: jest.fn(),
   renameWinArchive: jest.fn(),
   getGitHubHttpHeaders: jest.fn().mockReturnValue({Accept: 'application/json'})
 }));
 
-jest.mock('fs', () => ({
+const real_fs_module = await import('fs');
-  ...jest.requireActual('fs'),
+jest.unstable_mockModule('fs', () => ({
+  ...real_fs_module,
+  default: {
+    ...real_fs_module.default,
+    readdirSync: jest.fn(),
+    existsSync: jest.fn()
+  },
   readdirSync: jest.fn(),
   existsSync: jest.fn()
 }));
 
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const tc = await import('@actions/tool-cache');
+const http = await import('@actions/http-client');
+const fs = (await import('fs')).default;
+const util = await import('../../src/util.js');
+const {GraalVMCommunityDistribution, GraalVMDistribution} =
+  await import('../../src/distributions/graalvm/installer.js');
+const {getJavaDistribution} =
+  await import('../../src/distributions/distribution-factory.js');
+
+import type {JavaInstallerOptions} from '../../src/distributions/base-models.js';
+
 beforeAll(() => {
   process.env.NODE_ENV = 'test';
-
-  if (!jest.isMockFunction(http.HttpClient)) {
-    throw new Error('HTTP client must be mocked in tests!');
-  }
-
-  if (!jest.isMockFunction(tc.downloadTool)) {
-    throw new Error('Tool cache downloadTool must be mocked in tests!');
-  }
-
   console.log('✅ All external dependencies are properly mocked');
 });
 
 describe('GraalVMDistribution', () => {
-  let distribution: GraalVMDistribution;
+  let distribution: InstanceType<typeof GraalVMDistribution>;
-  let communityDistribution: GraalVMCommunityDistribution;
+  let communityDistribution: InstanceType<typeof GraalVMCommunityDistribution>;
-  let mockHttpClient: jest.Mocked<http.HttpClient>;
+  let mockHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   const defaultOptions: JavaInstallerOptions = {
     version: '17',
@@ -62,23 +125,20 @@ describe('GraalVMDistribution', () => {
     distribution = new GraalVMDistribution(defaultOptions);
     communityDistribution = new GraalVMCommunityDistribution(defaultOptions);
 
-    mockHttpClient = new http.HttpClient() as jest.Mocked<http.HttpClient>;
+    mockHttpClient = new (http.HttpClient as any)();
     (distribution as any).http = mockHttpClient;
     (communityDistribution as any).http = mockHttpClient;
 
-    (util.getDownloadArchiveExtension as jest.Mock).mockReturnValue('tar.gz');
+    (util.getDownloadArchiveExtension as jest.Mock<any>).mockReturnValue(
+      'tar.gz'
+    );
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
   afterAll(() => {
-    expect(jest.isMockFunction(http.HttpClient)).toBe(true);
-
-    expect(jest.isMockFunction(tc.downloadTool)).toBe(true);
-    expect(jest.isMockFunction(tc.cacheDir)).toBe(true);
-
     jest.restoreAllMocks();
     jest.clearAllMocks();
   });
@@ -113,20 +173,24 @@ describe('GraalVMDistribution', () => {
     };
 
     beforeEach(() => {
-      (tc.downloadTool as jest.Mock).mockResolvedValue('/tmp/archive.tar.gz');
+      (tc.downloadTool as any).mockResolvedValue('/tmp/archive.tar.gz');
-      (tc.cacheDir as jest.Mock).mockResolvedValue('/cached/java/path');
+      (tc.cacheDir as any).mockResolvedValue('/cached/java/path');
 
-      (util.extractJdkFile as jest.Mock).mockResolvedValue('/tmp/extracted');
+      (util.extractJdkFile as any).mockResolvedValue('/tmp/extracted');
 
       // Mock renameWinArchive - it returns the same path (no renaming)
-      (util.renameWinArchive as jest.Mock).mockImplementation((p: string) => p);
+      (util.renameWinArchive as any).mockImplementation((p: string) => p);
 
-      (util.getDownloadArchiveExtension as jest.Mock).mockReturnValue('tar.gz');
+      (util.getDownloadArchiveExtension as jest.Mock<any>).mockReturnValue(
+        'tar.gz'
+      );
 
       // Mock fs.existsSync to return true for extracted path
-      (fs.existsSync as jest.Mock).mockReturnValue(true);
+      (fs.existsSync as jest.Mock<any>).mockReturnValue(true);
 
-      (fs.readdirSync as jest.Mock).mockReturnValue(['graalvm-jdk-17.0.5']);
+      (fs.readdirSync as jest.Mock<any>).mockReturnValue([
+        'graalvm-jdk-17.0.5'
+      ]);
 
       jest
         .spyOn(distribution as any, 'getToolcacheVersionName')
@@ -173,7 +237,7 @@ describe('GraalVMDistribution', () => {
     });
 
     it('should throw error when extracted path does not exist', async () => {
-      (fs.existsSync as jest.Mock).mockReturnValue(false);
+      (fs.existsSync as jest.Mock<any>).mockReturnValue(false);
 
       await expect(
         (distribution as any).downloadTool(javaRelease)
@@ -187,8 +251,8 @@ describe('GraalVMDistribution', () => {
     });
 
     it('should throw error when extracted directory is empty', async () => {
-      (fs.existsSync as jest.Mock).mockReturnValue(true);
+      (fs.existsSync as jest.Mock<any>).mockReturnValue(true);
-      (fs.readdirSync as jest.Mock).mockReturnValue([]);
+      (fs.readdirSync as jest.Mock<any>).mockReturnValue([]);
 
       await expect(
         (distribution as any).downloadTool(javaRelease)
@@ -203,7 +267,7 @@ describe('GraalVMDistribution', () => {
 
     it('should handle download errors', async () => {
       const downloadError = new Error('Network error during download');
-      (tc.downloadTool as jest.Mock).mockRejectedValue(downloadError);
+      (tc.downloadTool as any).mockRejectedValue(downloadError);
 
       await expect(
         (distribution as any).downloadTool(javaRelease)
@@ -216,7 +280,7 @@ describe('GraalVMDistribution', () => {
 
     it('should handle extraction errors', async () => {
       const extractError = new Error('Failed to extract archive');
-      (util.extractJdkFile as jest.Mock).mockRejectedValue(extractError);
+      (util.extractJdkFile as any).mockRejectedValue(extractError);
 
       await expect(
         (distribution as any).downloadTool(javaRelease)
@@ -229,8 +293,10 @@ describe('GraalVMDistribution', () => {
 
     it('should handle different archive extensions', async () => {
       // Test with a .zip file
-      (util.getDownloadArchiveExtension as jest.Mock).mockReturnValue('zip');
+      (util.getDownloadArchiveExtension as jest.Mock<any>).mockReturnValue(
-      (tc.downloadTool as jest.Mock).mockResolvedValue('/tmp/archive.zip');
+        'zip'
+      );
+      (tc.downloadTool as any).mockResolvedValue('/tmp/archive.zip');
 
       const zipRelease = {
         version: '17.0.5',
@@ -309,7 +375,7 @@ describe('GraalVMDistribution', () => {
       it('should construct correct URL for specific version', async () => {
         const mockResponse = {
           message: {statusCode: 200}
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         const result = await (distribution as any).findPackageForDownload(
@@ -326,7 +392,7 @@ describe('GraalVMDistribution', () => {
       it('should construct correct URL for major version (latest)', async () => {
         const mockResponse = {
           message: {statusCode: 200}
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         const result = await (distribution as any).findPackageForDownload('21');
@@ -351,6 +417,61 @@ describe('GraalVMDistribution', () => {
         );
       });
 
+      describe('latest alias', () => {
+        it('resolves the newest major version from the Adoptium API', async () => {
+          const latestDistribution = new GraalVMDistribution({
+            ...defaultOptions,
+            version: 'latest'
+          });
+          (latestDistribution as any).http = mockHttpClient;
+          jest
+            .spyOn(latestDistribution, 'getPlatform')
+            .mockReturnValue('linux');
+          mockHttpClient.getJson.mockResolvedValue({
+            statusCode: 200,
+            result: {most_recent_feature_release: 25},
+            headers: {}
+          });
+          mockHttpClient.head.mockResolvedValue({
+            message: {statusCode: 200}
+          });
+
+          const result = await (
+            latestDistribution as any
+          ).findPackageForDownload('x');
+
+          expect(result).toEqual({
+            url: 'https://download.oracle.com/graalvm/25/latest/graalvm-jdk-25_linux-x64_bin.tar.gz',
+            version: '25'
+          });
+        });
+
+        it('throws an actionable error when the latest major is not yet available', async () => {
+          const latestDistribution = new GraalVMDistribution({
+            ...defaultOptions,
+            version: 'latest'
+          });
+          (latestDistribution as any).http = mockHttpClient;
+          jest
+            .spyOn(latestDistribution, 'getPlatform')
+            .mockReturnValue('linux');
+          mockHttpClient.getJson.mockResolvedValue({
+            statusCode: 200,
+            result: {most_recent_feature_release: 25},
+            headers: {}
+          });
+          mockHttpClient.head.mockResolvedValue({
+            message: {statusCode: 404}
+          });
+
+          await expect(
+            (latestDistribution as any).findPackageForDownload('x')
+          ).rejects.toThrow(
+            /is not yet available for the GraalVM distribution/
+          );
+        });
+      });
+
       it('should throw error for JDK versions less than 17', async () => {
         await expect(
           (distribution as any).findPackageForDownload('11')
@@ -374,7 +495,7 @@ describe('GraalVMDistribution', () => {
       it('should throw error when file not found (404)', async () => {
         const mockResponse = {
           message: {statusCode: 404}
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         // Verify the error is thrown with the expected message
@@ -395,7 +516,7 @@ describe('GraalVMDistribution', () => {
       it('should throw error for unauthorized access (401)', async () => {
         const mockResponse = {
           message: {statusCode: 401}
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         await expect(
@@ -408,7 +529,7 @@ describe('GraalVMDistribution', () => {
       it('should throw error for forbidden access (403)', async () => {
         const mockResponse = {
           message: {statusCode: 403}
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         await expect(
@@ -424,7 +545,7 @@ describe('GraalVMDistribution', () => {
             statusCode: 500,
             statusMessage: 'Internal Server Error'
           }
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         await expect(
@@ -437,7 +558,7 @@ describe('GraalVMDistribution', () => {
       it('should throw error for other HTTP errors without status message', async () => {
         const mockResponse = {
           message: {statusCode: 500}
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         await expect(
@@ -713,7 +834,7 @@ describe('GraalVMDistribution', () => {
       }
     ];
 
-    let fetchEASpy: jest.SpyInstance;
+    let fetchEASpy: any;
 
     beforeEach(() => {
       fetchEASpy = jest.spyOn(distribution as any, 'fetchEAJson');
@@ -932,7 +1053,7 @@ describe('GraalVMDistribution', () => {
 
         const mockResponse = {
           message: {statusCode: 200}
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         const result = await (distribution as any).findPackageForDownload('17');
@@ -960,7 +1081,7 @@ describe('GraalVMDistribution', () => {
 
         const mockResponse = {
           message: {statusCode: 200}
-        } as http.HttpClientResponse;
+        } as any;
         mockHttpClient.head.mockResolvedValue(mockResponse);
 
         const result = await (distribution as any).findPackageForDownload('17');
@@ -1049,6 +1170,60 @@ describe('GraalVMDistribution', () => {
         });
       });
 
+      it('resolves latest to the newest GA across all Community majors without calling Adoptium', async () => {
+        const latestCommunity = new GraalVMCommunityDistribution({
+          ...defaultOptions,
+          version: 'latest'
+        });
+        (latestCommunity as any).http = mockHttpClient;
+        jest.spyOn(latestCommunity, 'getPlatform').mockReturnValue('linux');
+
+        mockHttpClient.getJson.mockResolvedValue({
+          result: [
+            {
+              draft: false,
+              prerelease: false,
+              assets: [
+                {
+                  name: 'graalvm-community-jdk-21.0.2_linux-x64_bin.tar.gz',
+                  browser_download_url:
+                    'https://github.com/graalvm/graalvm-ce-builds/releases/download/jdk-21.0.2/graalvm-community-jdk-21.0.2_linux-x64_bin.tar.gz'
+                }
+              ]
+            },
+            {
+              draft: false,
+              prerelease: false,
+              assets: [
+                {
+                  name: 'graalvm-community-jdk-24.0.1_linux-x64_bin.tar.gz',
+                  browser_download_url:
+                    'https://github.com/graalvm/graalvm-ce-builds/releases/download/jdk-24.0.1/graalvm-community-jdk-24.0.1_linux-x64_bin.tar.gz'
+                }
+              ]
+            }
+          ],
+          statusCode: 200,
+          headers: {}
+        });
+
+        const result = await (latestCommunity as any).findPackageForDownload(
+          'x'
+        );
+
+        expect(result).toEqual({
+          url: 'https://github.com/graalvm/graalvm-ce-builds/releases/download/jdk-24.0.1/graalvm-community-jdk-24.0.1_linux-x64_bin.tar.gz',
+          version: '24.0.1'
+        });
+        // The Community release list is authoritative, so the Adoptium
+        // most_recent_feature_release endpoint must not be consulted.
+        expect(mockHttpClient.getJson).toHaveBeenCalledTimes(1);
+        expect(mockHttpClient.getJson).toHaveBeenCalledWith(
+          expect.stringContaining('graalvm-ce-builds/releases'),
+          expect.anything()
+        );
+      });
+
       it('should reject GraalVM Community early access requests', async () => {
         (communityDistribution as any).stable = false;
 

__tests__/distributors/jetbrains-installer.test.ts

@@ -1,14 +1,53 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
 import https from 'https';
 import {HttpClient} from '@actions/http-client';
-import {JetBrainsDistribution} from '../../src/distributions/jetbrains/installer';
 
-import manifestData from '../data/jetbrains.json';
+import manifestData from '../data/jetbrains.json' with {type: 'json'};
 import os from 'os';
-import * as core from '@actions/core';
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {JetBrainsDistribution} =
+  await import('../../src/distributions/jetbrains/installer.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -19,7 +58,7 @@ describe('getAvailableVersions', () => {
     });
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -31,11 +70,17 @@ describe('getAvailableVersions', () => {
 
   it('load available versions', async () => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
-    spyHttpClient.mockReturnValueOnce({
+    spyHttpClient
-      statusCode: 200,
+      .mockReturnValueOnce({
-      headers: {},
+        statusCode: 200,
-      result: manifestData as any
+        headers: {},
-    });
+        result: manifestData as any
+      })
+      .mockReturnValue({
+        statusCode: 200,
+        headers: {},
+        result: []
+      });
 
     const distribution = new JetBrainsDistribution({
       version: '17',

__tests__/distributors/kona-installer.test.ts

@@ -1,6 +1,6 @@
-import {KonaDistribution} from '../../src/distributions/kona/installer';
+import {KonaDistribution} from '../../src/distributions/kona/installer.js';
 
-import manifestData from '../data/kona.json';
+import manifestData from '../data/kona.json' with {type: 'json'};
 
 function mockDistr(
   version: string,

__tests__/distributors/liberica-installer.test.ts

@@ -1,17 +1,56 @@
-import {LibericaDistributions} from '../../src/distributions/liberica/installer';
 import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {
   ArchitectureOptions,
   LibericaVersion
-} from '../../src/distributions/liberica/models';
+} from '../../src/distributions/liberica/models.js';
 import {HttpClient} from '@actions/http-client';
 import os from 'os';
-import * as core from '@actions/core';
 
-import manifestData from '../data/liberica.json';
+import manifestData from '../data/liberica.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {LibericaDistributions} =
+  await import('../../src/distributions/liberica/installer.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -22,7 +61,7 @@ describe('getAvailableVersions', () => {
     });
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -184,7 +223,7 @@ describe('getArchitectureOptions', () => {
 });
 
 describe('findPackageForDownload', () => {
-  let distribution: LibericaDistributions;
+  let distribution: InstanceType<typeof LibericaDistributions>;
 
   beforeEach(() => {
     distribution = new LibericaDistributions({

__tests__/distributors/liberica-linux-installer.test.ts

@@ -1,17 +1,56 @@
-import {LibericaDistributions} from '../../src/distributions/liberica/installer';
 import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {
   ArchitectureOptions,
   LibericaVersion
-} from '../../src/distributions/liberica/models';
+} from '../../src/distributions/liberica/models.js';
 import {HttpClient} from '@actions/http-client';
 import os from 'os';
-import * as core from '@actions/core';
 
-import manifestData from '../data/liberica-linux.json';
+import manifestData from '../data/liberica-linux.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {LibericaDistributions} =
+  await import('../../src/distributions/liberica/installer.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -22,7 +61,7 @@ describe('getAvailableVersions', () => {
     });
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -184,7 +223,7 @@ describe('getArchitectureOptions', () => {
 });
 
 describe('findPackageForDownload', () => {
-  let distribution: LibericaDistributions;
+  let distribution: InstanceType<typeof LibericaDistributions>;
 
   beforeEach(() => {
     distribution = new LibericaDistributions({

__tests__/distributors/liberica-windows-installer.test.ts

@@ -1,17 +1,56 @@
-import {LibericaDistributions} from '../../src/distributions/liberica/installer';
 import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {
   ArchitectureOptions,
   LibericaVersion
-} from '../../src/distributions/liberica/models';
+} from '../../src/distributions/liberica/models.js';
 import {HttpClient} from '@actions/http-client';
 import os from 'os';
-import * as core from '@actions/core';
 
-import manifestData from '../data/liberica-windows.json';
+import manifestData from '../data/liberica-windows.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {LibericaDistributions} =
+  await import('../../src/distributions/liberica/installer.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -21,7 +60,7 @@ describe('getAvailableVersions', () => {
       result: manifestData as LibericaVersion[]
     });
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -183,7 +222,7 @@ describe('getArchitectureOptions', () => {
 });
 
 describe('findPackageForDownload', () => {
-  let distribution: LibericaDistributions;
+  let distribution: InstanceType<typeof LibericaDistributions>;
 
   beforeEach(() => {
     distribution = new LibericaDistributions({

__tests__/distributors/local-installer.test.ts

@@ -1,37 +1,101 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
 import fs from 'fs';
 
-import * as tc from '@actions/tool-cache';
-import * as core from '@actions/core';
-
 import path from 'path';
 import * as semver from 'semver';
-import * as util from '../../src/util';
 
-import {LocalDistribution} from '../../src/distributions/local/installer';
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+jest.unstable_mockModule('@actions/tool-cache', () => ({
+  find: jest.fn(),
+  findAllVersions: jest.fn(),
+  downloadTool: jest.fn(),
+  extractZip: jest.fn(),
+  extractTar: jest.fn(),
+  extract7z: jest.fn(),
+  extractXar: jest.fn(),
+  cacheDir: jest.fn(),
+  cacheFile: jest.fn(),
+  getManifestFromRepo: jest.fn(),
+  findFromManifest: jest.fn(),
+  evaluateVersions: jest.fn()
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  extractJdkFile: jest.fn(),
+  getDownloadArchiveExtension: jest.fn(),
+  getToolcachePath: jest.fn(),
+  isJobStatusSuccess: jest.fn(),
+  renameWinArchive: jest.fn(),
+  isVersionSatisfies: real_util_module.isVersionSatisfies,
+  getTempDir: real_util_module.getTempDir
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const tc = await import('@actions/tool-cache');
+const util = await import('../../src/util.js');
+const {LocalDistribution} =
+  await import('../../src/distributions/local/installer.js');
 
 describe('setupJava', () => {
   const actualJavaVersion = '11.1.10';
   const javaPath = path.join('Java_jdkfile_jdk', actualJavaVersion, 'x86');
 
-  let mockJavaBase: LocalDistribution;
+  let mockJavaBase: InstanceType<typeof LocalDistribution>;
 
-  let spyGetToolcachePath: jest.SpyInstance;
+  let spyGetToolcachePath: any;
-  let spyTcCacheDir: jest.SpyInstance;
+  let spyTcCacheDir: any;
-  let spyTcFindAllVersions: jest.SpyInstance;
+  let spyTcFindAllVersions: any;
-  let spyCoreDebug: jest.SpyInstance;
+  let spyCoreDebug: any;
-  let spyCoreInfo: jest.SpyInstance;
+  let spyCoreInfo: any;
-  let spyCoreExportVariable: jest.SpyInstance;
+  let spyCoreExportVariable: any;
-  let spyCoreAddPath: jest.SpyInstance;
+  let spyCoreAddPath: any;
-  let spyCoreSetOutput: jest.SpyInstance;
+  let spyCoreSetOutput: any;
-  let spyFsStat: jest.SpyInstance;
+  let spyFsStat: any;
-  let spyFsReadDir: jest.SpyInstance;
+  let spyFsReadDir: any;
-  let spyUtilsExtractJdkFile: jest.SpyInstance;
+  let spyUtilsExtractJdkFile: any;
-  let spyPathResolve: jest.SpyInstance;
+  let spyPathResolve: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
   const expectedJdkFile = 'JavaLocalJdkFile';
 
   beforeEach(() => {
-    spyGetToolcachePath = jest.spyOn(util, 'getToolcachePath');
+    spyGetToolcachePath = util.getToolcachePath as jest.Mock;
     spyGetToolcachePath.mockImplementation(
       (toolname: string, javaVersion: string, architecture: string) => {
         const semverVersion = new semver.Range(javaVersion);
@@ -49,7 +113,7 @@ describe('setupJava', () => {
       }
     );
 
-    spyTcCacheDir = jest.spyOn(tc, 'cacheDir');
+    spyTcCacheDir = tc.cacheDir as jest.Mock;
     spyTcCacheDir.mockImplementation(
       (
         archivePath: string,
@@ -59,23 +123,23 @@ describe('setupJava', () => {
       ) => path.join(toolcacheFolderName, version, architecture)
     );
 
-    spyTcFindAllVersions = jest.spyOn(tc, 'findAllVersions');
+    spyTcFindAllVersions = tc.findAllVersions as jest.Mock;
     spyTcFindAllVersions.mockReturnValue([actualJavaVersion]);
 
     // Spy on core methods
-    spyCoreDebug = jest.spyOn(core, 'debug');
+    spyCoreDebug = core.debug as jest.Mock;
     spyCoreDebug.mockImplementation(() => undefined);
 
-    spyCoreInfo = jest.spyOn(core, 'info');
+    spyCoreInfo = core.info as jest.Mock;
     spyCoreInfo.mockImplementation(() => undefined);
 
-    spyCoreAddPath = jest.spyOn(core, 'addPath');
+    spyCoreAddPath = core.addPath as jest.Mock;
     spyCoreAddPath.mockImplementation(() => undefined);
 
-    spyCoreExportVariable = jest.spyOn(core, 'exportVariable');
+    spyCoreExportVariable = core.exportVariable as jest.Mock;
     spyCoreExportVariable.mockImplementation(() => undefined);
 
-    spyCoreSetOutput = jest.spyOn(core, 'setOutput');
+    spyCoreSetOutput = core.setOutput as jest.Mock;
     spyCoreSetOutput.mockImplementation(() => undefined);
 
     // Spy on fs methods
@@ -88,7 +152,7 @@ describe('setupJava', () => {
     });
 
     // Spy on util methods
-    spyUtilsExtractJdkFile = jest.spyOn(util, 'extractJdkFile');
+    spyUtilsExtractJdkFile = util.extractJdkFile as jest.Mock;
     spyUtilsExtractJdkFile.mockImplementation(() => 'some/random/path/');
 
     // Spy on path methods
@@ -96,7 +160,7 @@ describe('setupJava', () => {
     spyPathResolve.mockImplementation((path: string) => path);
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -106,6 +170,20 @@ describe('setupJava', () => {
     jest.restoreAllMocks();
   });
 
+  it('throws for the latest alias since jdkfile has no version list', async () => {
+    const inputs = {
+      version: 'latest',
+      architecture: 'x86',
+      packageType: 'jdk',
+      checkLatest: false
+    };
+
+    mockJavaBase = new LocalDistribution(inputs, expectedJdkFile);
+    await expect(mockJavaBase.setupJava()).rejects.toThrow(
+      "The 'latest' version alias is not supported for the 'jdkfile' distribution. Please specify a concrete version."
+    );
+  });
+
   it('java is resolved from toolcache, jdkfile is untouched', async () => {
     const inputs = {
       version: actualJavaVersion,

__tests__/distributors/microsoft-installer.test.ts

@@ -1,23 +1,115 @@
 import {
-  MicrosoftDistributions,
+  jest,
-  MICROSOFT_PUBLIC_KEY
+  describe,
-} from '../../src/distributions/microsoft/installer';
+  it,
-import os from 'os';
+  expect,
-import data from '../data/microsoft.json';
+  beforeEach,
-import * as httpm from '@actions/http-client';
+  afterEach,
-import * as core from '@actions/core';
+  beforeAll,
-import * as tc from '@actions/tool-cache';
+  afterAll
-import * as gpg from '../../src/gpg';
+} from '@jest/globals';
-import * as util from '../../src/util';
+import {HttpClient} from '@actions/http-client';
-import fs from 'fs';
+import data from '../data/microsoft.json' with {type: 'json'};
+
+const mockOsArch = jest.fn(() => 'x64');
+const mockOsPlatform = jest.fn(() => 'linux');
+
+const real_os_module = await import('os');
+jest.unstable_mockModule('os', () => ({
+  ...real_os_module,
+  default: {
+    ...real_os_module.default,
+    arch: mockOsArch,
+    platform: mockOsPlatform,
+    homedir: real_os_module.default.homedir
+  },
+  arch: mockOsArch,
+  platform: mockOsPlatform
+}));
+
+const real_fs_module = await import('fs');
+const mockReaddirSync = jest.fn();
+jest.unstable_mockModule('fs', () => ({
+  ...real_fs_module,
+  default: {
+    ...real_fs_module.default,
+    readdirSync: mockReaddirSync
+  },
+  readdirSync: mockReaddirSync
+}));
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const real_tc_module = await import('@actions/tool-cache');
+jest.unstable_mockModule('@actions/tool-cache', () => ({
+  ...real_tc_module,
+  downloadTool: jest.fn(),
+  cacheDir: jest.fn(),
+  cacheFile: jest.fn()
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  extractJdkFile: jest.fn(),
+  getDownloadArchiveExtension: jest.fn(),
+  getToolcachePath: jest.fn(),
+  isJobStatusSuccess: jest.fn(),
+  renameWinArchive: jest.fn(),
+  isVersionSatisfies: real_util_module.isVersionSatisfies,
+  getTempDir: real_util_module.getTempDir
+}));
+
+jest.unstable_mockModule('../../src/gpg.js', () => ({
+  importKey: jest.fn(),
+  deleteKey: jest.fn(),
+  verifyPackageSignature: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const gpg = await import('../../src/gpg.js');
+const tc = await import('@actions/tool-cache');
+const os = (await import('os')).default;
+const fs = (await import('fs')).default;
+const {MicrosoftDistributions, MICROSOFT_PUBLIC_KEY} =
+  await import('../../src/distributions/microsoft/installer.js');
+const util = await import('../../src/util.js');
 
 describe('findPackageForDownload', () => {
-  let distribution: MicrosoftDistributions;
+  let distribution: InstanceType<typeof MicrosoftDistributions>;
-  let spyGetManifestFromRepo: jest.SpyInstance;
+  let spyGetManifestFromRepo: any;
-  let spyDebug: jest.SpyInstance;
+  let spyDebug: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
+    mockOsArch.mockReturnValue('x64');
+    mockOsPlatform.mockReturnValue(process.platform);
+
     distribution = new MicrosoftDistributions({
       version: '',
       architecture: 'x64',
@@ -25,18 +117,18 @@ describe('findPackageForDownload', () => {
       checkLatest: false
     });
 
-    spyGetManifestFromRepo = jest.spyOn(httpm.HttpClient.prototype, 'getJson');
+    spyGetManifestFromRepo = jest.spyOn(HttpClient.prototype, 'getJson');
     spyGetManifestFromRepo.mockReturnValue({
       result: data,
       statusCode: 200,
       headers: {}
     });
 
-    spyDebug = jest.spyOn(core, 'debug');
+    spyDebug = core.debug as jest.Mock;
     spyDebug.mockImplementation(() => {});
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -118,10 +210,8 @@ describe('findPackageForDownload', () => {
   ])(
     'defaults to os.arch(): %s mapped to distro arch: %s',
     async (osArch: string, distroArch: string) => {
-      jest
+      mockOsArch.mockReturnValue(osArch);
-        .spyOn(os, 'arch')
+      mockOsPlatform.mockReturnValue('darwin');
-        .mockReturnValue(osArch as ReturnType<typeof os.arch>);
-      jest.spyOn(os, 'platform').mockReturnValue('darwin');
 
       const version = '17';
       const distro = new MicrosoftDistributions({
@@ -144,10 +234,8 @@ describe('findPackageForDownload', () => {
   ])(
     'defaults to os.arch(): %s mapped to distro arch: %s',
     async (osArch: string, distroArch: string) => {
-      jest
+      mockOsArch.mockReturnValue(osArch);
-        .spyOn(os, 'arch')
+      mockOsPlatform.mockReturnValue('linux');
-        .mockReturnValue(osArch as ReturnType<typeof os.arch>);
-      jest.spyOn(os, 'platform').mockReturnValue('linux');
 
       const version = '17';
       const distro = new MicrosoftDistributions({
@@ -170,10 +258,8 @@ describe('findPackageForDownload', () => {
   ])(
     'defaults to os.arch(): %s mapped to distro arch: %s',
     async (osArch: string, distroArch: string) => {
-      jest
+      mockOsArch.mockReturnValue(osArch);
-        .spyOn(os, 'arch')
+      mockOsPlatform.mockReturnValue('win32');
-        .mockReturnValue(osArch as ReturnType<typeof os.arch>);
-      jest.spyOn(os, 'platform').mockReturnValue('win32');
 
       const version = '17';
       const distro = new MicrosoftDistributions({
@@ -217,7 +303,7 @@ describe('findPackageForDownload', () => {
       statusCode: 200,
       headers: {}
     });
-    jest.spyOn(os, 'platform').mockReturnValue('linux');
+    mockOsPlatform.mockReturnValue('linux');
 
     const result = await distribution['findPackageForDownload']('17.0.10');
 
@@ -228,16 +314,14 @@ describe('findPackageForDownload', () => {
 });
 
 describe('downloadTool', () => {
-  let spyDownloadTool: jest.SpyInstance;
+  let spyDownloadTool: any;
-  let spyExtractJdkFile: jest.SpyInstance;
+  let spyExtractJdkFile: any;
-  let spyCacheDir: jest.SpyInstance;
+  let spyCacheDir: any;
-  let spyVerifySignature: jest.SpyInstance;
+  let spyVerifySignature: any;
-  let distribution: MicrosoftDistributions;
+  let distribution: InstanceType<typeof MicrosoftDistributions>;
 
   beforeEach(() => {
-    jest
+    mockOsPlatform.mockReturnValue(process.platform);
-      .spyOn(os, 'platform')
-      .mockReturnValue(process.platform as ReturnType<typeof os.platform>);
 
     distribution = new MicrosoftDistributions({
       version: '17',
@@ -246,27 +330,27 @@ describe('downloadTool', () => {
       checkLatest: false
     });
 
-    spyDownloadTool = jest.spyOn(tc, 'downloadTool');
+    spyDownloadTool = tc.downloadTool as jest.Mock;
     spyDownloadTool.mockImplementation(async () => {
       return '/tmp/jdk.tar.gz';
     });
 
-    spyExtractJdkFile = jest.spyOn(util, 'extractJdkFile');
+    spyExtractJdkFile = util.extractJdkFile as jest.Mock;
     spyExtractJdkFile.mockImplementation(async () => {
       return '/tmp/unpacked';
     });
 
-    jest.spyOn(fs, 'readdirSync').mockReturnValue(['jdk'] as any);
+    mockReaddirSync.mockReturnValue(['jdk'] as any);
-    spyCacheDir = jest.spyOn(tc, 'cacheDir');
+    spyCacheDir = tc.cacheDir as jest.Mock;
     spyCacheDir.mockImplementation(async () => {
       return '/tmp/cached';
     });
 
-    jest
+    (util.renameWinArchive as jest.Mock<any>).mockImplementation(
-      .spyOn(util, 'renameWinArchive')
+      (archivePath: string) => `${archivePath}.zip`
-      .mockImplementation((archivePath: string) => `${archivePath}.zip`);
+    );
 
-    spyVerifySignature = jest.spyOn(gpg, 'verifyPackageSignature');
+    spyVerifySignature = gpg.verifyPackageSignature as jest.Mock;
     spyVerifySignature.mockImplementation(async () => {});
   });
 

__tests__/distributors/oracle-installer.test.ts

@@ -1,14 +1,53 @@
-import {OracleDistribution} from '../../src/distributions/oracle/installer';
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
 import os from 'os';
-import * as core from '@actions/core';
-import {getDownloadArchiveExtension} from '../../src/util';
 import {HttpClient} from '@actions/http-client';
 
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {OracleDistribution} =
+  await import('../../src/distributions/oracle/installer.js');
+const {getDownloadArchiveExtension} = await import('../../src/util.js');
+
 describe('findPackageForDownload', () => {
-  let distribution: OracleDistribution;
+  let distribution: InstanceType<typeof OracleDistribution>;
-  let spyDebug: jest.SpyInstance;
+  let spyDebug: any;
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     distribution = new OracleDistribution({
@@ -18,11 +57,11 @@ describe('findPackageForDownload', () => {
       checkLatest: false
     });
 
-    spyDebug = jest.spyOn(core, 'debug');
+    spyDebug = core.debug as jest.Mock;
     spyDebug.mockImplementation(() => {});
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -135,3 +174,59 @@ describe('findPackageForDownload', () => {
     );
   });
 });
+describe('findPackageForDownload with latest', () => {
+  let spyHttpClientHead: any;
+  let spyHttpClientGetJson: any;
+
+  beforeEach(() => {
+    (core.debug as jest.Mock).mockImplementation(() => {});
+    (core.error as jest.Mock).mockImplementation(() => {});
+    spyHttpClientGetJson = jest.spyOn(HttpClient.prototype, 'getJson');
+    spyHttpClientGetJson.mockResolvedValue({
+      statusCode: 200,
+      result: {most_recent_feature_release: 25},
+      headers: {}
+    });
+  });
+
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+
+  it('resolves the newest major version from the Adoptium API', async () => {
+    spyHttpClientHead = jest.spyOn(HttpClient.prototype, 'head');
+    spyHttpClientHead.mockResolvedValue({message: {statusCode: 200}});
+
+    const distribution = new OracleDistribution({
+      version: 'latest',
+      architecture: 'x64',
+      packageType: 'jdk',
+      checkLatest: false
+    });
+
+    const result = await distribution['findPackageForDownload']('x');
+    const osType = distribution.getPlatform();
+    const archiveType = getDownloadArchiveExtension();
+
+    expect(result.version).toBe('25');
+    expect(result.url).toBe(
+      `https://download.oracle.com/java/25/latest/jdk-25_${osType}-x64_bin.${archiveType}`
+    );
+  });
+
+  it('throws an actionable error when the latest major is not yet available', async () => {
+    spyHttpClientHead = jest.spyOn(HttpClient.prototype, 'head');
+    spyHttpClientHead.mockResolvedValue({message: {statusCode: 404}});
+
+    const distribution = new OracleDistribution({
+      version: 'latest',
+      architecture: 'x64',
+      packageType: 'jdk',
+      checkLatest: false
+    });
+
+    await expect(distribution['findPackageForDownload']('x')).rejects.toThrow(
+      /is not yet available for the Oracle JDK distribution/
+    );
+  });
+});

__tests__/distributors/sapmachine-installer.test.ts

@@ -1,14 +1,59 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
 import {HttpClient} from '@actions/http-client';
-import {SapMachineDistribution} from '../../src/distributions/sapmachine/installer';
-import * as utils from '../../src/util';
-import * as core from '@actions/core';
 
-import manifestData from '../data/sapmachine.json';
+import manifestData from '../data/sapmachine.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  getDownloadArchiveExtension: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {SapMachineDistribution} =
+  await import('../../src/distributions/sapmachine/installer.js');
+const utils = await import('../../src/util.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyUtilGetDownloadArchiveExtension: jest.SpyInstance;
+  let spyUtilGetDownloadArchiveExtension: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -18,14 +63,12 @@ describe('getAvailableVersions', () => {
       result: manifestData
     });
 
-    spyUtilGetDownloadArchiveExtension = jest.spyOn(
+    spyUtilGetDownloadArchiveExtension =
-      utils,
+      utils.getDownloadArchiveExtension as jest.Mock<any>;
-      'getDownloadArchiveExtension'
-    );
     spyUtilGetDownloadArchiveExtension.mockReturnValue('tar.gz');
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 
@@ -36,7 +79,7 @@ describe('getAvailableVersions', () => {
   });
 
   const mockPlatform = (
-    distribution: SapMachineDistribution,
+    distribution: InstanceType<typeof SapMachineDistribution>,
     platform: string
   ) => {
     distribution['getPlatformOption'] = () => platform;

__tests__/distributors/semeru-installer.test.ts

@@ -1,15 +1,53 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {JavaInstallerOptions} from '../../src/distributions/base-models.js';
 import {HttpClient} from '@actions/http-client';
 
-import {JavaInstallerOptions} from '../../src/distributions/base-models';
+import manifestData from '../data/semeru.json' with {type: 'json'};
-import {SemeruDistribution} from '../../src/distributions/semeru/installer';
 
-import manifestData from '../data/semeru.json';
+// Mock @actions/core before importing source modules that depend on it
-import * as core from '@actions/core';
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {SemeruDistribution} =
+  await import('../../src/distributions/semeru/installer.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
-  let spyCoreWarning: jest.SpyInstance;
+  let spyCoreWarning: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -19,9 +57,9 @@ describe('getAvailableVersions', () => {
       result: []
     });
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
-    spyCoreWarning = jest.spyOn(core, 'warning');
+    spyCoreWarning = core.warning as jest.Mock;
     spyCoreWarning.mockImplementation(() => {});
   });
 

__tests__/distributors/temurin-installer.test.ts

@@ -1,23 +1,92 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {JavaInstallerOptions} from '../../src/distributions/base-models.js';
+import type {TemurinImplementation as TemurinImplementationType} from '../../src/distributions/temurin/installer.js';
 import {HttpClient} from '@actions/http-client';
-import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import os from 'os';
-import {
-  TemurinDistribution,
-  TemurinImplementation,
-  ADOPTIUM_PUBLIC_KEY
-} from '../../src/distributions/temurin/installer';
-import {JavaInstallerOptions} from '../../src/distributions/base-models';
-import * as util from '../../src/util';
-import * as gpg from '../../src/gpg';
 
-import manifestData from '../data/temurin.json';
+import manifestData from '../data/temurin.json' with {type: 'json'};
-import * as core from '@actions/core';
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+jest.unstable_mockModule('@actions/tool-cache', () => ({
+  find: jest.fn(),
+  findAllVersions: jest.fn(),
+  downloadTool: jest.fn(),
+  extractZip: jest.fn(),
+  extractTar: jest.fn(),
+  extract7z: jest.fn(),
+  extractXar: jest.fn(),
+  cacheDir: jest.fn(),
+  cacheFile: jest.fn(),
+  getManifestFromRepo: jest.fn(),
+  findFromManifest: jest.fn(),
+  evaluateVersions: jest.fn()
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  extractJdkFile: jest.fn(),
+  getDownloadArchiveExtension: jest.fn(),
+  getToolcachePath: jest.fn(),
+  isJobStatusSuccess: jest.fn(),
+  renameWinArchive: jest.fn(),
+  isVersionSatisfies: real_util_module.isVersionSatisfies,
+  getTempDir: real_util_module.getTempDir
+}));
+
+jest.unstable_mockModule('../../src/gpg.js', () => ({
+  importKey: jest.fn(),
+  deleteKey: jest.fn(),
+  verifyPackageSignature: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const gpg = await import('../../src/gpg.js');
+const tc = await import('@actions/tool-cache');
+const {TemurinDistribution, TemurinImplementation, ADOPTIUM_PUBLIC_KEY} =
+  await import('../../src/distributions/temurin/installer.js');
+const util = await import('../../src/util.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
-  let spyCoreWarning: jest.SpyInstance;
+  let spyCoreWarning: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -27,9 +96,9 @@ describe('getAvailableVersions', () => {
       result: []
     });
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
-    spyCoreWarning = jest.spyOn(core, 'warning');
+    spyCoreWarning = core.warning as jest.Mock;
     spyCoreWarning.mockImplementation(() => {});
   });
 
@@ -84,7 +153,7 @@ describe('getAvailableVersions', () => {
     'build correct url for %s',
     async (
       installerOptions: JavaInstallerOptions,
-      impl: TemurinImplementation,
+      impl: TemurinImplementationType,
       expectedParameters
     ) => {
       const distribution = new TemurinDistribution(installerOptions, impl);
@@ -163,7 +232,11 @@ describe('getAvailableVersions', () => {
     [TemurinImplementation.Hotspot, 'jre', 'Java_Temurin-Hotspot_jre']
   ])(
     'find right toolchain folder',
-    (impl: TemurinImplementation, packageType: string, expected: string) => {
+    (
+      impl: TemurinImplementationType,
+      packageType: string,
+      expected: string
+    ) => {
       const distribution = new TemurinDistribution(
         {
           version: '8',
@@ -239,6 +312,24 @@ describe('findPackageForDownload', () => {
     expect(resolvedVersion.signatureUrl).toBeDefined();
   });
 
+  it('version "latest" is normalized to the newest available version', async () => {
+    const distribution = new TemurinDistribution(
+      {
+        version: 'latest',
+        architecture: 'x64',
+        packageType: 'jdk',
+        checkLatest: false
+      },
+      TemurinImplementation.Hotspot
+    );
+    distribution['getAvailableVersions'] = async () => manifestData as any;
+    // normalizeVersion turns `latest` into the wildcard carried on `this.version`
+    const resolvedVersion = await distribution['findPackageForDownload'](
+      distribution['version']
+    );
+    expect(resolvedVersion.version).toBe('16.0.2+7');
+  });
+
   it('version is found but binaries list is empty', async () => {
     const distribution = new TemurinDistribution(
       {
@@ -289,25 +380,25 @@ describe('findPackageForDownload', () => {
 });
 
 describe('downloadTool', () => {
-  let spyDownloadTool: jest.SpyInstance;
+  let spyDownloadTool: any;
-  let spyVerifySignature: jest.SpyInstance;
+  let spyVerifySignature: any;
-  let spyExtractJdkFile: jest.SpyInstance;
+  let spyExtractJdkFile: any;
-  let spyCacheDir: jest.SpyInstance;
+  let spyCacheDir: any;
-  let spyReadDirSync: jest.SpyInstance;
+  let spyReadDirSync: any;
-  let spyRenameWinArchive: jest.SpyInstance;
+  let spyRenameWinArchive: any;
 
   beforeEach(() => {
-    spyDownloadTool = jest.spyOn(tc, 'downloadTool');
+    spyDownloadTool = tc.downloadTool as jest.Mock;
     spyDownloadTool.mockResolvedValue('/tmp/jdk.tar.gz');
-    spyVerifySignature = jest.spyOn(gpg, 'verifyPackageSignature');
+    spyVerifySignature = gpg.verifyPackageSignature as jest.Mock;
     spyVerifySignature.mockResolvedValue(undefined);
-    spyExtractJdkFile = jest.spyOn(util, 'extractJdkFile');
+    spyExtractJdkFile = util.extractJdkFile as jest.Mock;
     spyExtractJdkFile.mockResolvedValue('/tmp/extracted');
-    spyCacheDir = jest.spyOn(tc, 'cacheDir');
+    spyCacheDir = tc.cacheDir as jest.Mock;
     spyCacheDir.mockResolvedValue('/tmp/toolcache');
     spyReadDirSync = jest.spyOn(fs, 'readdirSync');
     spyReadDirSync.mockReturnValue(['jdk-17'] as any);
-    spyRenameWinArchive = jest.spyOn(util, 'renameWinArchive');
+    spyRenameWinArchive = util.renameWinArchive as jest.Mock;
     spyRenameWinArchive.mockReturnValue('/tmp/jdk.tar.gz.zip');
   });
 

__tests__/distributors/zulu-installer.test.ts

@@ -1,16 +1,60 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {IZuluVersions} from '../../src/distributions/zulu/models.js';
 import {HttpClient} from '@actions/http-client';
-import {ZuluDistribution} from '../../src/distributions/zulu/installer';
-import {IZuluVersions} from '../../src/distributions/zulu/models';
-import * as utils from '../../src/util';
 import os from 'os';
-import * as core from '@actions/core';
 
-import manifestData from '../data/zulu-releases-default.json';
+import manifestData from '../data/zulu-releases-default.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  getDownloadArchiveExtension: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {ZuluDistribution} =
+  await import('../../src/distributions/zulu/installer.js');
+const utils = await import('../../src/util.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyUtilGetDownloadArchiveExtension: jest.SpyInstance;
+  let spyCoreError: any;
-  let spyCoreError: jest.SpyInstance;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -20,14 +64,12 @@ describe('getAvailableVersions', () => {
       result: [] as IZuluVersions[]
     });
 
-    spyUtilGetDownloadArchiveExtension = jest.spyOn(
+    (utils.getDownloadArchiveExtension as jest.Mock<any>).mockReturnValue(
-      utils,
+      'tar.gz'
-      'getDownloadArchiveExtension'
     );
-    spyUtilGetDownloadArchiveExtension.mockReturnValue('tar.gz');
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 

__tests__/distributors/zulu-linux-installer.test.ts

@@ -1,17 +1,62 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {IZuluVersions} from '../../src/distributions/zulu/models.js';
 import {HttpClient} from '@actions/http-client';
 import * as semver from 'semver';
-import {ZuluDistribution} from '../../src/distributions/zulu/installer';
-import {IZuluVersions} from '../../src/distributions/zulu/models';
-import * as utils from '../../src/util';
 import os from 'os';
-import * as core from '@actions/core';
 
-import manifestData from '../data/zulu-linux.json';
+import manifestData from '../data/zulu-linux.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  getDownloadArchiveExtension: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {ZuluDistribution} =
+  await import('../../src/distributions/zulu/installer.js');
+const utils = await import('../../src/util.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyUtilGetDownloadArchiveExtension: jest.SpyInstance;
+  let spyUtilGetDownloadArchiveExtension: any;
-  let spyCoreError: jest.SpyInstance;
+  let spyCoreError: any;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -21,14 +66,12 @@ describe('getAvailableVersions', () => {
       result: [] as IZuluVersions[]
     });
 
-    spyUtilGetDownloadArchiveExtension = jest.spyOn(
+    spyUtilGetDownloadArchiveExtension =
-      utils,
+      utils.getDownloadArchiveExtension as jest.Mock<any>;
-      'getDownloadArchiveExtension'
-    );
     spyUtilGetDownloadArchiveExtension.mockReturnValue('zip');
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 

__tests__/distributors/zulu-windows-installer.test.ts

@@ -1,17 +1,61 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import type {IZuluVersions} from '../../src/distributions/zulu/models.js';
 import {HttpClient} from '@actions/http-client';
 import * as semver from 'semver';
-import {ZuluDistribution} from '../../src/distributions/zulu/installer';
-import {IZuluVersions} from '../../src/distributions/zulu/models';
-import * as utils from '../../src/util';
 import os from 'os';
-import * as core from '@actions/core';
 
-import manifestData from '../data/zulu-windows.json';
+import manifestData from '../data/zulu-windows.json' with {type: 'json'};
+
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const real_util_module = await import('../../src/util.js');
+jest.unstable_mockModule('../../src/util.js', () => ({
+  ...real_util_module,
+  getDownloadArchiveExtension: jest.fn()
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const {ZuluDistribution} =
+  await import('../../src/distributions/zulu/installer.js');
+const utils = await import('../../src/util.js');
 
 describe('getAvailableVersions', () => {
-  let spyHttpClient: jest.SpyInstance;
+  let spyHttpClient: any;
-  let spyUtilGetDownloadArchiveExtension: jest.SpyInstance;
+  let spyCoreError: any;
-  let spyCoreError: jest.SpyInstance;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -21,14 +65,12 @@ describe('getAvailableVersions', () => {
       result: [] as IZuluVersions[]
     });
 
-    spyUtilGetDownloadArchiveExtension = jest.spyOn(
+    (utils.getDownloadArchiveExtension as jest.Mock<any>).mockReturnValue(
-      utils,
+      'zip'
-      'getDownloadArchiveExtension'
     );
-    spyUtilGetDownloadArchiveExtension.mockReturnValue('zip');
 
     // Mock core.error to suppress error logs
-    spyCoreError = jest.spyOn(core, 'error');
+    spyCoreError = core.error as jest.Mock;
     spyCoreError.mockImplementation(() => {});
   });
 

__tests__/gpg.test.ts

@@ -1,20 +1,29 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterAll,
+  afterEach
+} from '@jest/globals';
+import {fileURLToPath} from 'url';
 import * as path from 'path';
 import * as io from '@actions/io';
-import * as exec from '@actions/exec';
-import * as tc from '@actions/tool-cache';
-import * as gpg from '../src/gpg';
 
-jest.mock('@actions/exec', () => {
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
-  return {
-    exec: jest.fn()
-  };
-});
 
-jest.mock('@actions/tool-cache', () => {
+jest.unstable_mockModule('@actions/exec', () => ({
-  return {
+  exec: jest.fn()
-    downloadTool: jest.fn()
+}));
-  };
+
-});
+jest.unstable_mockModule('@actions/tool-cache', () => ({
+  downloadTool: jest.fn()
+}));
+
+const exec = await import('@actions/exec');
+const tc = await import('@actions/tool-cache');
+const gpg = await import('../src/gpg.js');
 
 const tempDir = path.join(__dirname, 'runner', 'temp');
 process.env['RUNNER_TEMP'] = tempDir;
@@ -92,7 +101,9 @@ describe('gpg tests', () => {
       it('imports bundled key and verifies package', async () => {
         const publicKeyContent =
           '-----BEGIN PGP PUBLIC KEY BLOCK-----\ntest\n-----END PGP PUBLIC KEY BLOCK-----';
-        (tc.downloadTool as jest.Mock).mockResolvedValue('/tmp/jdk.tar.gz.sig');
+        (tc.downloadTool as jest.Mock<any>).mockResolvedValue(
+          '/tmp/jdk.tar.gz.sig'
+        );
         await gpg.verifyPackageSignature(
           '/tmp/jdk.tar.gz',
           'https://example.com/jdk.tar.gz.sig',

__tests__/maven-args.test.ts

@@ -1,42 +1,68 @@
-import * as core from '@actions/core';
+import {afterEach, beforeEach, describe, expect, it, jest} from '@jest/globals';
 
-import {configureMavenArgs} from '../src/maven-args';
+const mockGetInput = jest.fn<(...args: any[]) => any>();
-import {
+const mockExportVariable = jest.fn<(...args: any[]) => any>();
+const mockInfo = jest.fn<(...args: any[]) => any>();
+const mockDebug = jest.fn<(...args: any[]) => any>();
+const mockWarning = jest.fn<(...args: any[]) => any>();
+
+jest.unstable_mockModule('@actions/core', () => ({
+  getInput: mockGetInput,
+  exportVariable: mockExportVariable,
+  info: mockInfo,
+  debug: mockDebug,
+  warning: mockWarning,
+  setSecret: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  addPath: jest.fn(),
+  getMultilineInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getState: jest.fn(),
+  saveState: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn(),
+  isDebug: jest.fn(),
+  setCommandEcho: jest.fn(),
+  getIDToken: jest.fn(),
+  ExitCode: {Success: 0, Failure: 1},
+  summary: {},
+  markdownSummary: {},
+  platform: {},
+  toPosixPath: jest.fn(),
+  toWin32Path: jest.fn(),
+  toPlatformPath: jest.fn()
+}));
+
+const {configureMavenArgs} = await import('../src/maven-args.js');
+const {
   INPUT_SHOW_DOWNLOAD_PROGRESS,
   MAVEN_ARGS_ENV,
   MAVEN_NO_TRANSFER_PROGRESS_FLAG
-} from '../src/constants';
+} = await import('../src/constants.js');
 
 describe('configureMavenArgs', () => {
   let inputs: Record<string, string>;
-  let spyGetInput: jest.SpyInstance;
-  let spyExportVariable: jest.SpyInstance;
-  let spyInfo: jest.SpyInstance;
-  let spyDebug: jest.SpyInstance;
   const originalMavenArgs = process.env[MAVEN_ARGS_ENV];
 
   beforeEach(() => {
     inputs = {};
 
-    spyGetInput = jest.spyOn(core, 'getInput');
+    mockGetInput.mockImplementation((name: string) => inputs[name] ?? '');
-    spyGetInput.mockImplementation((name: string) => inputs[name] ?? '');
+    mockExportVariable.mockImplementation((name: string, value: string) => {
-
-    spyExportVariable = jest.spyOn(core, 'exportVariable');
-    spyExportVariable.mockImplementation((name: string, value: string) => {
       process.env[name] = value;
     });
-
+    mockInfo.mockImplementation(() => undefined);
-    spyInfo = jest.spyOn(core, 'info');
+    mockDebug.mockImplementation(() => undefined);
-    spyInfo.mockImplementation(() => undefined);
-
-    spyDebug = jest.spyOn(core, 'debug');
-    spyDebug.mockImplementation(() => undefined);
 
     delete process.env[MAVEN_ARGS_ENV];
   });
 
   afterEach(() => {
-    jest.restoreAllMocks();
+    jest.resetAllMocks();
     if (originalMavenArgs === undefined) {
       delete process.env[MAVEN_ARGS_ENV];
     } else {
@@ -47,7 +73,7 @@ describe('configureMavenArgs', () => {
   it('sets MAVEN_ARGS with -ntp by default', () => {
     configureMavenArgs();
 
-    expect(spyExportVariable).toHaveBeenCalledWith(
+    expect(mockExportVariable).toHaveBeenCalledWith(
       MAVEN_ARGS_ENV,
       MAVEN_NO_TRANSFER_PROGRESS_FLAG
     );
@@ -59,7 +85,7 @@ describe('configureMavenArgs', () => {
 
     configureMavenArgs();
 
-    expect(spyExportVariable).not.toHaveBeenCalled();
+    expect(mockExportVariable).not.toHaveBeenCalled();
     expect(process.env[MAVEN_ARGS_ENV]).toBeUndefined();
   });
 
@@ -68,7 +94,7 @@ describe('configureMavenArgs', () => {
 
     configureMavenArgs();
 
-    expect(spyExportVariable).toHaveBeenCalledWith(
+    expect(mockExportVariable).toHaveBeenCalledWith(
       MAVEN_ARGS_ENV,
       `-B -Dstyle.color=always ${MAVEN_NO_TRANSFER_PROGRESS_FLAG}`
     );
@@ -79,7 +105,7 @@ describe('configureMavenArgs', () => {
 
     configureMavenArgs();
 
-    expect(spyExportVariable).not.toHaveBeenCalled();
+    expect(mockExportVariable).not.toHaveBeenCalled();
     expect(process.env[MAVEN_ARGS_ENV]).toBe('-B -ntp');
   });
 
@@ -88,7 +114,7 @@ describe('configureMavenArgs', () => {
 
     configureMavenArgs();
 
-    expect(spyExportVariable).not.toHaveBeenCalled();
+    expect(mockExportVariable).not.toHaveBeenCalled();
     expect(process.env[MAVEN_ARGS_ENV]).toBe('--no-transfer-progress -B');
   });
 
@@ -98,7 +124,7 @@ describe('configureMavenArgs', () => {
 
     configureMavenArgs();
 
-    expect(spyExportVariable).not.toHaveBeenCalled();
+    expect(mockExportVariable).not.toHaveBeenCalled();
     expect(process.env[MAVEN_ARGS_ENV]).toBe('-B');
   });
 });

__tests__/toolchains.test.ts

@@ -1,23 +1,63 @@
+import {
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+  beforeAll,
+  afterAll
+} from '@jest/globals';
+import {fileURLToPath} from 'url';
 import * as fs from 'fs';
 import os from 'os';
 import * as path from 'path';
-import * as core from '@actions/core';
 import * as io from '@actions/io';
-import * as toolchains from '../src/toolchains';
-import {M2_DIR, MVN_TOOLCHAINS_FILE} from '../src/constants';
 
+// Mock @actions/core before importing source modules that depend on it
+jest.unstable_mockModule('@actions/core', () => ({
+  info: jest.fn(),
+  warning: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  setFailed: jest.fn(),
+  setOutput: jest.fn(),
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+// Dynamic imports after mocking
+const core = await import('@actions/core');
+const toolchains = await import('../src/toolchains.js');
+const {M2_DIR, MVN_TOOLCHAINS_FILE} = await import('../src/constants.js');
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 const m2Dir = path.join(__dirname, M2_DIR);
 const toolchainsFile = path.join(m2Dir, MVN_TOOLCHAINS_FILE);
 
 describe('toolchains tests', () => {
-  let spyOSHomedir: jest.SpyInstance;
+  let spyOSHomedir: any;
-  let spyInfo: jest.SpyInstance;
+  let spyInfo: any;
 
   beforeEach(async () => {
     await io.rmRF(m2Dir);
     spyOSHomedir = jest.spyOn(os, 'homedir');
     spyOSHomedir.mockReturnValue(__dirname);
-    spyInfo = jest.spyOn(core, 'info');
+    spyInfo = core.info as jest.Mock;
     spyInfo.mockImplementation(() => null);
   }, 300000);
 
@@ -895,6 +935,11 @@ describe('toolchains tests', () => {
     const jdkHome =
       '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64';
 
+    (core.getInput as jest.Mock<any>).mockImplementation((name: string) => {
+      if (name === 'settings-path') return m2Dir;
+      return '';
+    });
+
     await toolchains.configureToolchains(
       version,
       distributionName,

__tests__/util.test.ts

@@ -1,19 +1,64 @@
-import * as cache from '@actions/cache';
+import {
-import * as core from '@actions/core';
+  jest,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterAll,
+  afterEach
+} from '@jest/globals';
+import {fileURLToPath} from 'url';
 import * as fs from 'fs';
 import * as path from 'path';
-import {
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+
+// Mock @actions/cache
+jest.unstable_mockModule('@actions/cache', () => ({
+  isFeatureAvailable: jest.fn(),
+  saveCache: jest.fn(),
+  restoreCache: jest.fn()
+}));
+
+// Mock @actions/core
+jest.unstable_mockModule('@actions/core', () => ({
+  getInput: jest.fn(),
+  getBooleanInput: jest.fn(),
+  getMultilineInput: jest.fn(),
+  setOutput: jest.fn(),
+  setFailed: jest.fn(),
+  warning: jest.fn(),
+  info: jest.fn(),
+  debug: jest.fn(),
+  error: jest.fn(),
+  notice: jest.fn(),
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  addPath: jest.fn(),
+  exportVariable: jest.fn(),
+  saveState: jest.fn(),
+  getState: jest.fn(),
+  setSecret: jest.fn(),
+  isDebug: jest.fn(() => false),
+  group: jest.fn((_name: string, fn: () => Promise<unknown>) => fn()),
+  toPlatformPath: jest.fn((p: string) => p),
+  toWin32Path: jest.fn((p: string) => p),
+  toPosixPath: jest.fn((p: string) => p)
+}));
+
+const cache = await import('@actions/cache');
+const core = await import('@actions/core');
+
+const {
   convertVersionToSemver,
   getNextPageUrlFromLinkHeader,
   getVersionFromFileContent,
   isVersionSatisfies,
   isCacheFeatureAvailable,
   isGhes,
-  validatePaginationUrl
+  validatePaginationUrl,
-} from '../src/util';
+  getLatestMajorVersion
-
+} = await import('../src/util.js');
-jest.mock('@actions/cache');
-jest.mock('@actions/core');
 
 describe('isVersionSatisfies', () => {
   it.each([
@@ -45,8 +90,10 @@ describe('isVersionSatisfies', () => {
 
 describe('isCacheFeatureAvailable', () => {
   it('isCacheFeatureAvailable disabled on GHES', () => {
-    jest.spyOn(cache, 'isFeatureAvailable').mockImplementation(() => false);
+    (cache.isFeatureAvailable as jest.Mock<any>).mockImplementation(
-    const infoMock = jest.spyOn(core, 'warning');
+      () => false
+    );
+    const infoMock = core.warning as jest.Mock;
     const message =
       'Caching is only supported on GHES version >= 3.5. If you are on a version >= 3.5, please check with your GHES admin if the Actions cache service is enabled or not.';
     try {
@@ -59,8 +106,10 @@ describe('isCacheFeatureAvailable', () => {
   });
 
   it('isCacheFeatureAvailable disabled on dotcom', () => {
-    jest.spyOn(cache, 'isFeatureAvailable').mockImplementation(() => false);
+    (cache.isFeatureAvailable as jest.Mock<any>).mockImplementation(
-    const infoMock = jest.spyOn(core, 'warning');
+      () => false
+    );
+    const infoMock = core.warning as jest.Mock;
     const message =
       'The runner was not able to contact the cache service. Caching will be skipped';
     try {
@@ -73,9 +122,14 @@ describe('isCacheFeatureAvailable', () => {
   });
 
   it('isCacheFeatureAvailable is enabled', () => {
-    jest.spyOn(cache, 'isFeatureAvailable').mockImplementation(() => true);
+    (cache.isFeatureAvailable as jest.Mock<any>).mockImplementation(() => true);
     expect(isCacheFeatureAvailable()).toBe(true);
   });
+
+  afterEach(() => {
+    jest.resetAllMocks();
+    jest.clearAllMocks();
+  });
 });
 
 describe('convertVersionToSemver', () => {
@@ -315,7 +369,6 @@ describe('isGhes', () => {
   const pristineEnv = process.env;
 
   beforeEach(() => {
-    jest.resetModules();
     process.env = {...pristineEnv};
   });
 
@@ -348,3 +401,33 @@ describe('isGhes', () => {
     expect(isGhes()).toBeTruthy();
   });
 });
+
+describe('getLatestMajorVersion', () => {
+  const makeHttp = (getJson: jest.Mock) =>
+    ({getJson}) as unknown as import('@actions/http-client').HttpClient;
+
+  it('returns most_recent_feature_release from the Adoptium API', async () => {
+    const getJson = jest.fn(async () => ({
+      statusCode: 200,
+      result: {most_recent_feature_release: 25},
+      headers: {}
+    }));
+
+    await expect(getLatestMajorVersion(makeHttp(getJson))).resolves.toBe(25);
+    expect(getJson).toHaveBeenCalledWith(
+      'https://api.adoptium.net/v3/info/available_releases'
+    );
+  });
+
+  it('throws when the response does not contain a usable value', async () => {
+    const getJson = jest.fn(async () => ({
+      statusCode: 200,
+      result: {},
+      headers: {}
+    }));
+
+    await expect(getLatestMajorVersion(makeHttp(getJson))).rejects.toThrow(
+      'Could not determine the latest available Java major version'
+    );
+  });
+});

action.yml

@@ -4,7 +4,7 @@ description: 'Set up a specific version of the Java JDK and add the
 author: 'GitHub'
 inputs:
   java-version:
-    description: 'The Java version to set up. Takes a whole or semver Java version. See examples of supported syntax in README file'
+    description: 'The Java version to set up. Takes a whole or semver Java version, or the "latest" alias to use the newest available stable release. See examples of supported syntax in README file'
     required: false
   java-version-file:
     description: 'The path to a file containing the Java version to set up (.java-version, .tool-versions, .sdkmanrc). Used when java-version is not set. See examples of supported syntax in README file'

dist/cleanup/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}

dist/setup/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}

docs/advanced-usage.md

@@ -15,6 +15,7 @@
   - [Tencent Kona](#Tencent-Kona)
 - [Installing custom Java package type](#Installing-custom-Java-package-type)
   - [JavaFX Maven project](#JavaFX-Maven-project)
+- [Ensuring the Maven cache is complete (plugin dependencies)](#ensuring-the-maven-cache-is-complete-plugin-dependencies)
 - [Installing custom Java architecture](#Installing-custom-Java-architecture)
 - [Installing JDK without setting as default](#Installing-JDK-without-setting-as-default)
 - [Installing custom Java distribution from local file](#Installing-Java-from-local-file)
@@ -285,6 +286,122 @@ To run the JavaFX application in CI:
   run: mvn --no-transfer-progress javafx:run
 ```
 
+## Ensuring the Maven cache is complete (plugin dependencies)
+
+When you enable `cache: maven`, the action caches your local Maven repository
+(`~/.m2/repository`) and downloaded Maven Wrapper distributions
+(`~/.m2/wrapper/dists`). The cache key is a hash of your Maven inputs — every
+`**/pom.xml`, plus `**/.mvn/wrapper/maven-wrapper.properties` and
+`**/.mvn/extensions.xml` — so changing any of those files (for example bumping
+the wrapper version or editing core extensions) produces a new key and
+invalidates the cache. At the end of the job the action saves whatever was
+downloaded during that run. It does **not** re-save the cache when the key
+already matches (a cache *hit*).
+
+Maven resolves **plugin** dependencies lazily: it only downloads the plugins and
+plugin dependencies required by the goals that actually execute. As a result, the
+run that first creates the cache determines what is stored. If that run executed a
+"thin" goal such as `mvn compile`, plugins bound to later phases are never
+resolved. For example, `maven-shade-plugin` (bound to `package`) pulls in
+`plexus-archiver`, `commons-compress`, `io.airlift:aircompressor` and
+`org.tukaani:xz` — none of which a `compile` run downloads. Those artifacts are
+therefore absent from the cache, and because the action does not re-save on a
+hit, every later `test`/`verify`/`package` job re-downloads them on every run.
+
+### Seed the cache with a resolution step
+
+To populate `~/.m2` as comprehensively as possible on the run that creates the
+cache, run a dependency-resolution "seed" command before your build. Choose a
+command based on how thorough you need it to be:
+
+| Seed command | Resolves plugin dependencies? | Notes |
+|--------------|:-----------------------------:|-------|
+| `mvn dependency:resolve` | No | Resolves project dependencies only — misses plugin dependencies (e.g. `aircompressor`). |
+| `mvn dependency:resolve-plugins` | Yes | Resolves plugins **and their dependencies**. |
+| `mvn dependency:go-offline` | Yes | Resolves project and plugin dependencies (a superset). |
+| `mvn dependency:go-offline dependency:resolve-plugins` | Yes (most thorough) | Recommended default. Use `dependency:resolve dependency:resolve-plugins` if `go-offline` is flaky or insufficient for your project. |
+
+Single job — seed, then build (the cache saved at the end of this run contains
+the full set):
+
+```yaml
+steps:
+- uses: actions/checkout@v6
+- uses: actions/setup-java@v5
+  with:
+    distribution: 'temurin'
+    java-version: '25'
+    cache: 'maven'
+- name: Seed the Maven cache
+  run: mvn -B dependency:go-offline dependency:resolve-plugins
+- name: Build with Maven
+  run: mvn -B verify --file pom.xml
+```
+
+Separate seed job — useful for a matrix where different legs run different goals
+(`test`, `check`, `verify`, `-Pprofile1`, ...) but all share the same `~/.m2`
+cache. Without a seed, whichever job finishes first creates the cache from its
+own partial `.m2`, and parallel jobs race to save an equally partial cache; the
+seed job instead creates one comprehensive cache that every other job reuses:
+
+```yaml
+jobs:
+  seed-cache:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6
+    - uses: actions/setup-java@v5
+      with:
+        distribution: 'temurin'
+        java-version: '25'
+        cache: 'maven'
+    - name: Seed the Maven cache
+      run: mvn -B dependency:go-offline dependency:resolve-plugins
+
+  build:
+    needs: seed-cache
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        goal: ['test', 'verify', 'test -Pprofile1']
+    steps:
+    - uses: actions/checkout@v6
+    - uses: actions/setup-java@v5
+      with:
+        distribution: 'temurin'
+        java-version: '25'
+        cache: 'maven'
+    - name: Build
+      run: mvn -B ${{ matrix.goal }} --file pom.xml
+```
+
+### Caveats
+
+- **The seed only helps on the run that creates the cache.** Once a cache exists
+  for the current `pom.xml` hash, later runs get a hit and any additional
+  downloads are not saved. On an existing repository whose cache is already
+  incomplete, invalidate it once (for example by changing `cache-dependency-path`
+  or deleting the repository's caches) so a complete cache is created from the
+  seed.
+- **Static resolution is not exhaustive.** `go-offline`/`resolve-plugins` resolve
+  the statically declared plugin set for the *active* profiles and modules.
+  Profile-gated plugins, conditionally-active modules, and artifacts a plugin
+  fetches at execution time may still be missed. For the most complete cache,
+  seed with the fullest goal set your CI actually uses (for example
+  `mvn -B verify` with every profile enabled).
+- **Multi-module projects:** run the seed at the reactor root so every module's
+  plugins are resolved.
+
+> [!NOTE]
+> The same "the cache stores only what the creating run downloaded, and is not
+> re-saved on a hit" behavior applies to `cache: gradle`, since Gradle also
+> resolves dependencies and plugin/buildscript classpaths lazily. Gradle has no
+> direct equivalent of `dependency:go-offline`, so for complete and fine-grained
+> dependency caching on Gradle projects we recommend
+> [`gradle/actions/setup-gradle`](https://github.com/gradle/actions/tree/main/setup-gradle),
+> which provides purpose-built caching (see the
+> [setup-gradle documentation](https://github.com/gradle/actions/blob/main/docs/setup-gradle.md)).
+
 ## Installing custom Java architecture
 
 ```yaml

eslint.config.mjs

@@ -0,0 +1,74 @@
+// This is a reusable configuration file copied from https://github.com/actions/reusable-workflows/tree/main/reusable-configurations. Please don't make changes to this file as it's the subject of an automatic update.
+import js from '@eslint/js';
+import tsParser from '@typescript-eslint/parser';
+import tsPlugin from '@typescript-eslint/eslint-plugin';
+import jest from 'eslint-plugin-jest';
+import n from 'eslint-plugin-n';
+import prettier from 'eslint-config-prettier';
+import globals from 'globals';
+
+export default [
+  {
+    ignores: ['**/*', '!src/**', '!__tests__/**']
+  },
+  js.configs.recommended,
+  {
+    files: ['**/*.ts'],
+    languageOptions: {
+      parser: tsParser,
+      ecmaVersion: 2022,
+      sourceType: 'module',
+      globals: {
+        ...globals.node,
+        ...globals.es2015
+      }
+    },
+    plugins: {
+      '@typescript-eslint': tsPlugin,
+      n
+    },
+    rules: {
+      ...tsPlugin.configs.recommended.rules,
+      '@typescript-eslint/no-require-imports': 'error',
+      '@typescript-eslint/no-non-null-assertion': 'off',
+      '@typescript-eslint/no-explicit-any': 'off',
+      '@typescript-eslint/no-empty-function': 'off',
+      '@typescript-eslint/ban-ts-comment': [
+        'error',
+        {
+          'ts-ignore': 'allow-with-description'
+        }
+      ],
+      'no-console': 'error',
+      yoda: 'error',
+      'prefer-const': [
+        'error',
+        {
+          destructuring: 'all'
+        }
+      ],
+      'no-control-regex': 'off',
+      'no-constant-condition': ['error', {checkLoops: false}],
+      'no-undef': 'off',
+      'no-useless-assignment': 'off',
+      'n/no-extraneous-import': 'error'
+    }
+  },
+  {
+    files: ['**/*{test,spec}.ts'],
+    plugins: {jest},
+    languageOptions: {
+      globals: {
+        ...globals.jest
+      }
+    },
+    rules: {
+      ...jest.configs['flat/recommended'].rules,
+      '@typescript-eslint/no-unused-vars': 'off',
+      'jest/no-standalone-expect': 'off',
+      'jest/no-conditional-expect': 'off',
+      'no-console': 'off'
+    }
+  },
+  prettier
+];

jest.config.js

@@ -1,11 +0,0 @@
-module.exports = {
-  clearMocks: true,
-  moduleFileExtensions: ['js', 'ts'],
-  testEnvironment: 'node',
-  testMatch: ['**/*.test.ts'],
-  testRunner: 'jest-circus/runner',
-  transform: {
-    '^.+\\.ts$': 'ts-jest'
-  },
-  verbose: true
-}

jest.config.ts

@@ -0,0 +1,24 @@
+export default {
+  clearMocks: true,
+  moduleFileExtensions: ['js', 'ts'],
+  roots: ['<rootDir>'],
+  testEnvironment: 'node',
+  testMatch: ['**/*.test.ts'],
+  transform: {
+    '^.+\\.ts$': [
+      'ts-jest',
+      {
+        useESM: true,
+        diagnostics: {
+          ignoreCodes: [151002]
+        }
+      }
+    ]
+  },
+  extensionsToTreatAsEsm: ['.ts'],
+  transformIgnorePatterns: ['node_modules/(?!(@actions)/)'],
+  moduleNameMapper: {
+    '^(\\.{1,2}/.*)\\.js$': '$1'
+  },
+  verbose: true
+}

package.json

@@ -1,6 +1,7 @@
 {
   "name": "setup-java",
-  "version": "5.6.0",
+  "version": "6.0.0",
+  "type": "module",
   "private": true,
   "description": "setup java action",
   "main": "dist/setup/index.js",
@@ -9,24 +10,24 @@
   },
   "scripts": {
     "build": "ncc build -o dist/setup src/setup-java.ts && ncc build -o dist/cleanup src/cleanup-java.ts",
-    "format": "prettier --no-error-on-unmatched-pattern --config ./.prettierrc.js --write \"**/*.{ts,yml,yaml}\"",
+    "format": "prettier --no-error-on-unmatched-pattern --write \"**/*.{ts,yml,yaml}\"",
-    "format-check": "prettier --no-error-on-unmatched-pattern --config ./.prettierrc.js --check \"**/*.{ts,yml,yaml}\"",
+    "format-check": "prettier --no-error-on-unmatched-pattern --check \"**/*.{ts,yml,yaml}\"",
-    "lint": "eslint --config ./.eslintrc.js \"**/*.ts\"",
+    "lint": "eslint \"**/*.ts\"",
-    "lint:fix": "eslint --config ./.eslintrc.js \"**/*.ts\" --fix",
+    "lint:fix": "eslint \"**/*.ts\" --fix",
     "check": "npm run format-check && npm run lint && npm run build && npm test",
     "fix": "npm run format && npm run lint:fix && npm run build",
     "prepare": "husky install",
     "prerelease": "npm run-script build",
     "release": "git add -f dist/setup/index.js dist/cleanup/index.js",
-    "test": "jest"
+    "test": "node --experimental-vm-modules ./node_modules/jest/bin/jest.js --runInBand --coverage"
   },
   "lint-staged": {
     "*.ts": [
-      "prettier --no-error-on-unmatched-pattern --config ./.prettierrc.js --write",
+      "prettier --no-error-on-unmatched-pattern --write",
-      "eslint --config ./.eslintrc.js --fix"
+      "eslint --fix"
     ],
     "*.{yml,yaml}": [
-      "prettier --no-error-on-unmatched-pattern --config ./.prettierrc.js --write"
+      "prettier --no-error-on-unmatched-pattern --write"
     ]
   },
   "repository": {
@@ -41,34 +42,35 @@
   "author": "GitHub",
   "license": "MIT",
   "dependencies": {
-    "@actions/cache": "^5.1.0",
+    "@actions/cache": "^6.1.0",
-    "@actions/core": "^2.0.3",
+    "@actions/core": "^3.0.1",
-    "@actions/exec": "^2.0.0",
+    "@actions/exec": "^3.0.0",
-    "@actions/glob": "^0.5.1",
+    "@actions/glob": "^0.7.0",
-    "@actions/http-client": "^3.0.2",
+    "@actions/http-client": "^4.0.1",
-    "@actions/io": "^2.0.0",
+    "@actions/io": "^3.0.2",
-    "@actions/tool-cache": "^3.0.1",
+    "@actions/tool-cache": "^4.0.0",
-    "semver": "^7.6.0",
+    "semver": "^7.8.5",
     "xmlbuilder2": "^4.0.3"
   },
   "devDependencies": {
-    "@types/jest": "^30.0.0",
+    "@eslint/js": "^10.0.1",
+    "@jest/globals": "^30.4.1",
     "@types/node": "^26.0.0",
-    "@types/semver": "^7.5.8",
+    "@types/semver": "^7.7.0",
-    "@typescript-eslint/eslint-plugin": "^8.48.0",
+    "@typescript-eslint/eslint-plugin": "^8.62.0",
     "@typescript-eslint/parser": "^8.62.0",
     "@vercel/ncc": "^0.44.0",
-    "eslint": "^8.57.0",
+    "eslint": "^10.5.0",
     "eslint-config-prettier": "^10.1.8",
     "eslint-plugin-jest": "^29.15.4",
-    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-n": "^18.1.0",
+    "globals": "^17.7.0",
     "husky": "^9.1.7",
     "jest": "^30.4.2",
-    "jest-circus": "^30.4.2",
     "lint-staged": "^17.0.8",
     "prettier": "^3.9.1",
     "ts-jest": "^29.4.11",
-    "typescript": "^5.3.3"
+    "typescript": "^6.0.3"
   },
   "bugs": {
     "url": "https://github.com/actions/setup-java/issues"

src/auth.ts

@@ -6,9 +6,9 @@ import * as fs from 'fs';
 import * as os from 'os';
 
 import {create as xmlCreate} from 'xmlbuilder2';
-import * as constants from './constants';
+import * as constants from './constants.js';
-import * as gpg from './gpg';
+import * as gpg from './gpg.js';
-import {getBooleanInput} from './util';
+import {getBooleanInput} from './util.js';
 
 export async function configureAuthentication() {
   const id = core.getInput(constants.INPUT_SERVER_ID);

src/cleanup-java.ts

@@ -1,8 +1,9 @@
 import * as core from '@actions/core';
-import * as gpg from './gpg';
+import * as gpg from './gpg.js';
-import * as constants from './constants';
+import * as constants from './constants.js';
-import {isJobStatusSuccess} from './util';
+import {isJobStatusSuccess} from './util.js';
-import {save} from './cache';
+import {save} from './cache.js';
+import {fileURLToPath} from 'url';
 
 async function removePrivateKeyFromKeychain() {
   if (core.getInput(constants.INPUT_GPG_PRIVATE_KEY, {required: false})) {
@@ -52,7 +53,7 @@ export async function run() {
   await ignoreError(saveCache());
 }
 
-if (require.main === module) {
+if (process.argv[1] === fileURLToPath(import.meta.url)) {
   run();
 } else {
   // https://nodejs.org/api/modules.html#modules_accessing_the_main_module

src/distributions/adopt/installer.ts

@@ -5,13 +5,13 @@ import fs from 'fs';
 import path from 'path';
 import semver from 'semver';
 
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
-import {IAdoptAvailableVersions} from './models';
+import {IAdoptAvailableVersions} from './models.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import {
   extractJdkFile,
   getNextPageUrlFromLinkHeader,
@@ -20,8 +20,11 @@ import {
   renameWinArchive,
   MAX_PAGINATION_PAGES,
   validatePaginationUrl
-} from '../../util';
+} from '../../util.js';
-import {TemurinDistribution, TemurinImplementation} from '../temurin/installer';
+import {
+  TemurinDistribution,
+  TemurinImplementation
+} from '../temurin/installer.js';
 
 export enum AdoptImplementation {
   Hotspot = 'Hotspot',

src/distributions/base-installer.ts

@@ -4,13 +4,17 @@ import * as fs from 'fs';
 import semver from 'semver';
 import path from 'path';
 import * as httpm from '@actions/http-client';
-import {getToolcachePath, isVersionSatisfies} from '../util';
+import {
+  convertVersionToSemver,
+  getToolcachePath,
+  isVersionSatisfies
+} from '../util.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from './base-models';
+} from './base-models.js';
-import {MACOS_JAVA_CONTENT_POSTFIX} from '../constants';
+import {MACOS_JAVA_CONTENT_POSTFIX} from '../constants.js';
 import os from 'os';
 
 export abstract class JavaBase {
@@ -19,6 +23,7 @@ export abstract class JavaBase {
   protected architecture: string;
   protected packageType: string;
   protected stable: boolean;
+  protected latest: boolean;
   protected checkLatest: boolean;
   protected setDefault: boolean;
   protected verifySignature: boolean;
@@ -33,9 +38,11 @@ export abstract class JavaBase {
       maxRetries: 3
     });
 
-    ({version: this.version, stable: this.stable} = this.normalizeVersion(
+    ({
-      installerOptions.version
+      version: this.version,
-    ));
+      stable: this.stable,
+      latest: this.latest
+    } = this.normalizeVersion(installerOptions.version));
     this.architecture = installerOptions.architecture || os.arch();
     this.packageType = installerOptions.packageType;
     this.checkLatest = installerOptions.checkLatest;
@@ -62,7 +69,7 @@ export abstract class JavaBase {
     }
 
     let foundJava = this.findInToolcache();
-    if (foundJava && !this.checkLatest) {
+    if (foundJava && !this.checkLatest && !this.latest) {
       core.info(`Resolved Java ${foundJava.version} from tool-cache`);
     } else {
       core.info('Trying to resolve the latest version from remote');
@@ -263,6 +270,30 @@ export abstract class JavaBase {
 
   protected normalizeVersion(version: string) {
     let stable = true;
+    const latest = false;
+
+    // Support the `latest` alias (case-insensitive), which floats to the newest
+    // available stable/GA release. It is translated to the SemVer wildcard `x`
+    // so the existing "newest satisfying version wins" resolution applies.
+    const normalized = version.trim().toLowerCase();
+    if (normalized === 'latest') {
+      return {
+        version: 'x',
+        stable: true,
+        latest: true
+      };
+    }
+
+    // Reject `latest` combined with any qualifier (e.g. `latest-ea`). Such inputs
+    // would otherwise have their `-ea` suffix stripped and fall through to the
+    // generic SemVer check, which fails with a confusing "'latest' is not valid
+    // SemVer" message even though `latest` is a supported value. Fail early with a
+    // targeted explanation instead.
+    if (normalized.startsWith('latest')) {
+      throw new Error(
+        `The 'latest' alias resolves stable (GA) releases only and cannot be combined with '-ea' or other qualifiers (received '${version}'). Use 'latest' on its own, or specify a concrete version.`
+      );
+    }
 
     if (version.endsWith('-ea')) {
       version = version.replace(/-ea$/, '');
@@ -273,6 +304,15 @@ export abstract class JavaBase {
       stable = false;
     }
 
+    // Java uses a versioning scheme (JEP 322) that can contain more numeric
+    // fields than SemVer allows, e.g. '18.0.1.1' or '11.0.9.1'. Convert such
+    // exact versions to SemVer build notation ('18.0.1+1') so they are
+    // accepted. Ranges and versions that already carry build metadata are
+    // left untouched.
+    if (/^\d+(\.\d+){3,}$/.test(version)) {
+      version = convertVersionToSemver(version);
+    }
+
     if (!semver.validRange(version)) {
       throw new Error(
         `The string '${version}' is not valid SemVer notation for a Java version. Please check README file for code snippets and more detailed information`
@@ -281,7 +321,8 @@ export abstract class JavaBase {
 
     return {
       version,
-      stable
+      stable,
+      latest
     };
   }
 

src/distributions/corretto/installer.ts

@@ -7,17 +7,17 @@ import {
   getDownloadArchiveExtension,
   convertVersionToSemver,
   renameWinArchive
-} from '../../util';
+} from '../../util.js';
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import {
   ICorrettoAllAvailableVersions,
   ICorrettoAvailableVersions
-} from './models';
+} from './models.js';
 
 export class CorrettoDistribution extends JavaBase {
   constructor(installerOptions: JavaInstallerOptions) {
@@ -59,10 +59,28 @@ export class CorrettoDistribution extends JavaBase {
     if (!this.stable) {
       throw new Error('Early access versions are not supported');
     }
+    const availableVersions = await this.getAvailableVersions();
+
+    // The `latest` alias is normalized to the SemVer wildcard, but Corretto
+    // matches on an exact major version, so resolve it to the newest available
+    // major from Corretto's own list.
+    if (this.latest) {
+      const majors = availableVersions
+        .map(item => parseInt(item.version, 10))
+        .filter(major => Number.isFinite(major) && major > 0);
+
+      if (majors.length === 0) {
+        throw new Error(
+          'Could not determine the latest available Corretto major version from remote metadata'
+        );
+      }
+
+      version = Math.max(...majors).toString();
+    }
+
     if (version.includes('.')) {
       throw new Error('Only major versions are supported');
     }
-    const availableVersions = await this.getAvailableVersions();
     const matchingVersions = availableVersions
       .filter(item => item.version == version)
       .map(item => {

src/distributions/distribution-factory.ts

@@ -1,22 +1,25 @@
-import {JavaBase} from './base-installer';
+import {JavaBase} from './base-installer.js';
-import {JavaInstallerOptions} from './base-models';
+import {JavaInstallerOptions} from './base-models.js';
-import {LocalDistribution} from './local/installer';
+import {LocalDistribution} from './local/installer.js';
-import {ZuluDistribution} from './zulu/installer';
+import {ZuluDistribution} from './zulu/installer.js';
-import {AdoptDistribution, AdoptImplementation} from './adopt/installer';
+import {AdoptDistribution, AdoptImplementation} from './adopt/installer.js';
-import {TemurinDistribution, TemurinImplementation} from './temurin/installer';
+import {
-import {LibericaDistributions} from './liberica/installer';
+  TemurinDistribution,
-import {MicrosoftDistributions} from './microsoft/installer';
+  TemurinImplementation
-import {SemeruDistribution} from './semeru/installer';
+} from './temurin/installer.js';
-import {CorrettoDistribution} from './corretto/installer';
+import {LibericaDistributions} from './liberica/installer.js';
-import {OracleDistribution} from './oracle/installer';
+import {MicrosoftDistributions} from './microsoft/installer.js';
-import {DragonwellDistribution} from './dragonwell/installer';
+import {SemeruDistribution} from './semeru/installer.js';
-import {SapMachineDistribution} from './sapmachine/installer';
+import {CorrettoDistribution} from './corretto/installer.js';
+import {OracleDistribution} from './oracle/installer.js';
+import {DragonwellDistribution} from './dragonwell/installer.js';
+import {SapMachineDistribution} from './sapmachine/installer.js';
 import {
   GraalVMCommunityDistribution,
   GraalVMDistribution
-} from './graalvm/installer';
+} from './graalvm/installer.js';
-import {JetBrainsDistribution} from './jetbrains/installer';
+import {JetBrainsDistribution} from './jetbrains/installer.js';
-import {KonaDistribution} from './kona/installer';
+import {KonaDistribution} from './kona/installer.js';
 
 enum JavaDistribution {
   Adopt = 'adopt',

src/distributions/dragonwell/installer.ts

@@ -5,7 +5,7 @@ import semver from 'semver';
 import fs from 'fs';
 import path from 'path';
 
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {
   convertVersionToSemver,
   extractJdkFile,
@@ -13,13 +13,13 @@ import {
   getGitHubHttpHeaders,
   isVersionSatisfies,
   renameWinArchive
-} from '../../util';
+} from '../../util.js';
-import {IDragonwellVersions, IDragonwellAllVersions} from './models';
+import {IDragonwellVersions, IDragonwellAllVersions} from './models.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 
 export class DragonwellDistribution extends JavaBase {
   constructor(installerOptions: JavaInstallerOptions) {

src/distributions/graalvm/installer.ts

@@ -3,25 +3,26 @@ import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import path from 'path';
 import semver from 'semver';
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {HttpCodes} from '@actions/http-client';
-import {GraalVMEAVersion} from './models';
+import {GraalVMEAVersion} from './models.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import {
   convertVersionToSemver,
   extractJdkFile,
   getDownloadArchiveExtension,
   getGitHubHttpHeaders,
+  getLatestMajorVersion,
   getNextPageUrlFromLinkHeader,
   isVersionSatisfies,
   MAX_PAGINATION_PAGES,
   renameWinArchive,
   validatePaginationUrl
-} from '../../util';
+} from '../../util.js';
 
 const GRAALVM_DL_BASE = 'https://download.oracle.com/graalvm';
 const GRAALVM_DOWNLOAD_URL = 'https://www.graalvm.org/downloads/';
@@ -119,6 +120,13 @@ export class GraalVMDistribution extends JavaBase {
       return this.findEABuildDownloadUrl(`${range}-ea`);
     }
 
+    // The `latest` alias is normalized to the SemVer wildcard. Oracle GraalVM
+    // builds its download URLs from a concrete major and has no endpoint to list
+    // releases, so resolve the newest available GA major from the Adoptium API.
+    if (this.latest) {
+      range = (await getLatestMajorVersion(this.http)).toString();
+    }
+
     const {platform, extension, major} = this.validateStableBuildRequest(range);
 
     const fileUrl = this.constructFileUrl(
@@ -203,6 +211,9 @@ export class GraalVMDistribution extends JavaBase {
     if (statusCode === HttpCodes.NotFound) {
       // Create the standard error with additional hint about checking the download URL
       const error = this.createVersionNotFoundError(range);
+      if (this.latest) {
+        error.message += `\nThe latest Java major version (${range}) is not yet available for the ${this.distribution} distribution. Please specify a concrete version instead of 'latest'.`;
+      }
       error.message += `\nPlease check if this version is available at ${GRAALVM_DOWNLOAD_URL} . Pick a version from the list.`;
       throw error;
     }
@@ -300,17 +311,20 @@ export class GraalVMDistribution extends JavaBase {
         // Check if it's a 404 error (file not found)
         if (error.message?.includes('404')) {
           throw new Error(
-            `GraalVM EA version '${javaEaVersion}' not found. Please verify the version exists in the EA builds repository.`
+            `GraalVM EA version '${javaEaVersion}' not found. Please verify the version exists in the EA builds repository.`,
+            {cause: error}
           );
         }
         // Re-throw with more context
         throw new Error(
-          `Failed to fetch GraalVM EA version information for '${javaEaVersion}': ${error.message}`
+          `Failed to fetch GraalVM EA version information for '${javaEaVersion}': ${error.message}`,
+          {cause: error}
         );
       }
       // If it's not an Error instance, throw a generic error
       throw new Error(
-        `Failed to fetch GraalVM EA version information for '${javaEaVersion}'`
+        `Failed to fetch GraalVM EA version information for '${javaEaVersion}'`,
+        {cause: error}
       );
     }
   }
@@ -351,7 +365,27 @@ export class GraalVMCommunityDistribution extends GraalVMDistribution {
     }
 
     const arch = this.getSupportedArchitecture();
-    const {platform, extension} = this.validateStableBuildRequest(range);
+
+    // GraalVM Community publishes its releases on GitHub, so the `latest` alias
+    // (normalized to the SemVer wildcard `x`) can float to the newest GA it
+    // actually ships. Unlike Oracle GraalVM (which has no listing endpoint and
+    // must derive the newest major from the Adoptium API), we match against the
+    // real release list here, so `latest` never fails when GraalVM lags behind a
+    // brand-new Java major.
+    let platform: OsVersions;
+    let extension: string;
+    if (this.latest) {
+      if (this.packageType !== 'jdk') {
+        throw new Error(
+          `${this.distribution} provides only the \`jdk\` package type`
+        );
+      }
+      platform = this.getPlatform();
+      extension = getDownloadArchiveExtension();
+    } else {
+      ({platform, extension} = this.validateStableBuildRequest(range));
+    }
+
     // GraalVM Community asset names embed the platform, architecture and
     // archive type, e.g. `graalvm-community-jdk-21.0.2_linux-x64_bin.tar.gz`.
     const assetSuffix = `_${platform}-${arch}_bin.${extension}`;

src/distributions/jetbrains/installer.ts

@@ -5,14 +5,14 @@ import fs from 'fs';
 import path from 'path';
 import semver from 'semver';
 
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
-import {IJetBrainsRawVersion, IJetBrainsVersion} from './models';
+import {IJetBrainsRawVersion, IJetBrainsVersion} from './models.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
-import {extractJdkFile, isVersionSatisfies} from '../../util';
+import {extractJdkFile, isVersionSatisfies} from '../../util.js';
 import {OutgoingHttpHeaders} from 'http';
 import {HttpCodes} from '@actions/http-client';
 

src/distributions/kona/installer.ts

@@ -5,19 +5,19 @@ import semver from 'semver';
 import fs from 'fs';
 import path from 'path';
 
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
-import {IKonaReleaseInfo, IKonaRelease} from './models';
+import {IKonaReleaseInfo, IKonaRelease} from './models.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import {
   extractJdkFile,
   getDownloadArchiveExtension,
   isVersionSatisfies,
   renameWinArchive
-} from '../../util';
+} from '../../util.js';
 
 export class KonaDistribution extends JavaBase {
   constructor(installerOptions: JavaInstallerOptions) {

src/distributions/liberica/installer.ts

@@ -1,18 +1,18 @@
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import semver from 'semver';
 import {
   extractJdkFile,
   getDownloadArchiveExtension,
   isVersionSatisfies,
   renameWinArchive
-} from '../../util';
+} from '../../util.js';
 import * as core from '@actions/core';
-import {ArchitectureOptions, LibericaVersion, OsVersions} from './models';
+import {ArchitectureOptions, LibericaVersion, OsVersions} from './models.js';
 import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import path from 'path';

src/distributions/local/installer.ts

@@ -4,14 +4,14 @@ import * as core from '@actions/core';
 import fs from 'fs';
 import path from 'path';
 
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {
   JavaInstallerOptions,
   JavaDownloadRelease,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
-import {extractJdkFile} from '../../util';
+import {extractJdkFile} from '../../util.js';
-import {MACOS_JAVA_CONTENT_POSTFIX} from '../../constants';
+import {MACOS_JAVA_CONTENT_POSTFIX} from '../../constants.js';
 
 export class LocalDistribution extends JavaBase {
   constructor(
@@ -22,6 +22,12 @@ export class LocalDistribution extends JavaBase {
   }
 
   public async setupJava(): Promise<JavaInstallerResults> {
+    if (this.latest) {
+      throw new Error(
+        "The 'latest' version alias is not supported for the 'jdkfile' distribution. Please specify a concrete version."
+      );
+    }
+
     let foundJava = this.findInToolcache();
 
     if (foundJava) {

src/distributions/microsoft/installer.ts

@@ -1,24 +1,24 @@
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import {
   extractJdkFile,
   getDownloadArchiveExtension,
   getGitHubHttpHeaders,
   renameWinArchive
-} from '../../util';
+} from '../../util.js';
-import * as gpg from '../../gpg';
+import * as gpg from '../../gpg.js';
-import {MICROSOFT_PUBLIC_KEY} from './microsoft-key';
+import {MICROSOFT_PUBLIC_KEY} from './microsoft-key.js';
 import * as core from '@actions/core';
 import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import path from 'path';
 import {TypedResponse} from '@actions/http-client/lib/interfaces';
 
-export {MICROSOFT_PUBLIC_KEY} from './microsoft-key';
+export {MICROSOFT_PUBLIC_KEY} from './microsoft-key.js';
 
 export class MicrosoftDistributions extends JavaBase {
   constructor(installerOptions: JavaInstallerOptions) {
@@ -48,7 +48,8 @@ export class MicrosoftDistributions extends JavaBase {
         );
       } catch (error) {
         throw new Error(
-          `Failed to verify signature for Microsoft Build of OpenJDK version ${javaRelease.version}. Signature URL: ${javaRelease.signatureUrl}. Error: ${(error as Error).message}`
+          `Failed to verify signature for Microsoft Build of OpenJDK version ${javaRelease.version}. Signature URL: ${javaRelease.signatureUrl}. Error: ${(error as Error).message}`,
+          {cause: error}
         );
       }
     }

src/distributions/oracle/installer.ts

@@ -4,18 +4,20 @@ import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import path from 'path';
 
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import {
   extractJdkFile,
   getDownloadArchiveExtension,
+  getLatestMajorVersion,
   renameWinArchive
-} from '../../util';
+} from '../../util.js';
 import {HttpCodes} from '@actions/http-client';
+import {OsVersions} from './models.js';
 
 const ORACLE_DL_BASE = 'https://download.oracle.com/java';
 
@@ -72,6 +74,14 @@ export class OracleDistribution extends JavaBase {
     const platform = this.getPlatform();
     const extension = getDownloadArchiveExtension();
 
+    // The `latest` alias is normalized to the SemVer wildcard. Oracle builds its
+    // download URLs from a concrete major and has no endpoint to list releases,
+    // so resolve the newest available GA major from the Adoptium API and use it.
+    if (this.latest) {
+      const latestMajor = await getLatestMajorVersion(this.http);
+      range = latestMajor.toString();
+    }
+
     const isOnlyMajorProvided = !range.includes('.');
     const major = isOnlyMajorProvided ? range : range.split('.')[0];
 
@@ -112,6 +122,12 @@ export class OracleDistribution extends JavaBase {
       }
     }
 
+    if (this.latest) {
+      const error = this.createVersionNotFoundError(range);
+      error.message += `\nThe latest Java major version (${range}) is not yet available for the Oracle JDK distribution. Please specify a concrete version instead of 'latest'.`;
+      throw error;
+    }
+
     throw this.createVersionNotFoundError(range);
   }
 

src/distributions/sapmachine/installer.ts

@@ -10,14 +10,14 @@ import {
   getDownloadArchiveExtension,
   isVersionSatisfies,
   renameWinArchive
-} from '../../util';
+} from '../../util.js';
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
-import {ISapMachineAllVersions, ISapMachineVersions} from './models';
+import {ISapMachineAllVersions, ISapMachineVersions} from './models.js';
 
 export class SapMachineDistribution extends JavaBase {
   constructor(installerOptions: JavaInstallerOptions) {

src/distributions/semeru/installer.ts

@@ -1,9 +1,9 @@
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import semver from 'semver';
 import {
   extractJdkFile,
@@ -13,12 +13,12 @@ import {
   renameWinArchive,
   MAX_PAGINATION_PAGES,
   validatePaginationUrl
-} from '../../util';
+} from '../../util.js';
 import * as core from '@actions/core';
 import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import path from 'path';
-import {ISemeruAvailableVersions} from './models';
+import {ISemeruAvailableVersions} from './models.js';
 
 const supportedArchitectures = [
   'x64',

src/distributions/temurin/installer.ts

@@ -4,16 +4,16 @@ import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import path from 'path';
 import semver from 'semver';
-import * as gpg from '../../gpg';
+import * as gpg from '../../gpg.js';
 
-import {ADOPTIUM_PUBLIC_KEY} from './adoptium-key';
+import {ADOPTIUM_PUBLIC_KEY} from './adoptium-key.js';
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
-import {ITemurinAvailableVersions} from './models';
+import {ITemurinAvailableVersions} from './models.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 import {
   extractJdkFile,
   getNextPageUrlFromLinkHeader,
@@ -22,9 +22,9 @@ import {
   renameWinArchive,
   MAX_PAGINATION_PAGES,
   validatePaginationUrl
-} from '../../util';
+} from '../../util.js';
 
-export {ADOPTIUM_PUBLIC_KEY} from './adoptium-key';
+export {ADOPTIUM_PUBLIC_KEY} from './adoptium-key.js';
 
 export enum TemurinImplementation {
   Hotspot = 'Hotspot'
@@ -102,7 +102,8 @@ export class TemurinDistribution extends JavaBase {
         throw new Error(
           `Failed to verify signature for Temurin version ${javaRelease.version} from ${javaRelease.signatureUrl}: ${
             (error as Error).message
-          }`
+          }`,
+          {cause: error}
         );
       }
     }

src/distributions/zulu/installer.ts

@@ -5,20 +5,20 @@ import path from 'path';
 import fs from 'fs';
 import semver from 'semver';
 
-import {JavaBase} from '../base-installer';
+import {JavaBase} from '../base-installer.js';
-import {IZuluVersions} from './models';
+import {IZuluVersions} from './models.js';
 import {
   extractJdkFile,
   getDownloadArchiveExtension,
   convertVersionToSemver,
   isVersionSatisfies,
   renameWinArchive
-} from '../../util';
+} from '../../util.js';
 import {
   JavaDownloadRelease,
   JavaInstallerOptions,
   JavaInstallerResults
-} from '../base-models';
+} from '../base-models.js';
 
 export class ZuluDistribution extends JavaBase {
   constructor(installerOptions: JavaInstallerOptions) {

src/gpg.ts

@@ -3,8 +3,8 @@ import * as path from 'path';
 import * as io from '@actions/io';
 import * as exec from '@actions/exec';
 import * as tc from '@actions/tool-cache';
-import * as util from './util';
+import * as util from './util.js';
-import {ExecOptions} from '@actions/exec/lib/interfaces';
+import {ExecOptions} from '@actions/exec';
 
 export const PRIVATE_KEY_FILE = path.join(util.getTempDir(), 'private-key.asc');
 
@@ -86,7 +86,8 @@ export async function verifyPackageSignature(
     throw new Error(
       `Failed to create temporary GPG home directory for signature verification: ${
         (error as Error).message
-      }`
+      }`,
+      {cause: error}
     );
   }
   try {

src/maven-args.ts

@@ -1,11 +1,11 @@
 import * as core from '@actions/core';
-import {getBooleanInput} from './util';
+import {getBooleanInput} from './util.js';
 import {
   INPUT_SHOW_DOWNLOAD_PROGRESS,
   MAVEN_ARGS_ENV,
   MAVEN_NO_TRANSFER_PROGRESS_FLAG,
   MAVEN_NO_TRANSFER_PROGRESS_LONG_FLAG
-} from './constants';
+} from './constants.js';
 
 /**
  * Configures the MAVEN_ARGS environment variable so that Maven suppresses

src/setup-java.ts

@@ -1,18 +1,19 @@
 import fs from 'fs';
 import * as core from '@actions/core';
-import * as auth from './auth';
+import * as auth from './auth.js';
 import {
   getBooleanInput,
   isCacheFeatureAvailable,
   getVersionFromFileContent
-} from './util';
+} from './util.js';
-import * as toolchains from './toolchains';
+import * as toolchains from './toolchains.js';
-import * as constants from './constants';
+import * as constants from './constants.js';
-import {restore} from './cache';
+import {restore} from './cache.js';
 import * as path from 'path';
-import {getJavaDistribution} from './distributions/distribution-factory';
+import {fileURLToPath} from 'url';
-import {JavaInstallerOptions} from './distributions/base-models';
+import {getJavaDistribution} from './distributions/distribution-factory.js';
-import {configureMavenArgs} from './maven-args';
+import {JavaInstallerOptions} from './distributions/base-models.js';
+import {configureMavenArgs} from './maven-args.js';
 
 async function run() {
   try {
@@ -113,7 +114,12 @@ async function run() {
       }
     }
     core.endGroup();
-    const matchersPath = path.join(__dirname, '..', '..', '.github');
+    const matchersPath = path.join(
+      path.dirname(fileURLToPath(import.meta.url)),
+      '..',
+      '..',
+      '.github'
+    );
     core.info(`##[add-matcher]${path.join(matchersPath, 'java.json')}`);
 
     await auth.configureAuthentication();
@@ -180,8 +186,14 @@ async function installVersion(
   }
 
   const result = await distribution.setupJava();
+
+  // When the `latest` alias is used, the literal input isn't a real version, so
+  // pass the resolved version to the toolchains configuration instead.
+  const isLatest = version.trim().toLowerCase() === 'latest';
+  const toolchainVersion = isLatest ? result.version : version;
+
   await toolchains.configureToolchains(
-    version,
+    toolchainVersion,
     distributionName,
     result.path,
     toolchainIds[toolchainId]

src/toolchains.ts

@@ -3,9 +3,9 @@ import * as os from 'os';
 import * as path from 'path';
 import * as core from '@actions/core';
 import * as io from '@actions/io';
-import * as constants from './constants';
+import * as constants from './constants.js';
 
-import {getBooleanInput} from './util';
+import {getBooleanInput} from './util.js';
 import {create as xmlCreate} from 'xmlbuilder2';
 
 interface JdkInfo {

src/util.ts

@@ -6,7 +6,11 @@ import * as cache from '@actions/cache';
 import * as core from '@actions/core';
 
 import * as tc from '@actions/tool-cache';
-import {INPUT_JOB_STATUS, DISTRIBUTIONS_ONLY_MAJOR_VERSION} from './constants';
+import * as httpm from '@actions/http-client';
+import {
+  INPUT_JOB_STATUS,
+  DISTRIBUTIONS_ONLY_MAJOR_VERSION
+} from './constants.js';
 import {OutgoingHttpHeaders} from 'http';
 
 export function getTempDir() {
@@ -379,3 +383,33 @@ export function renameWinArchive(javaArchivePath: string): string {
   fs.renameSync(javaArchivePath, javaArchivePathRenamed);
   return javaArchivePathRenamed;
 }
+
+interface IAdoptiumAvailableReleases {
+  most_recent_feature_release: number;
+}
+
+// Resolve the newest available stable/GA feature (major) release.
+//
+// Some distributions (e.g. Oracle, GraalVM) construct their download URLs from a
+// concrete major version and don't expose an endpoint to list every available
+// release, so a bare `latest` alias can't be resolved from their own metadata.
+// The Adoptium (Temurin) API is used as a proxy for "what is the newest GA major
+// version out there", which those distributions typically publish at the same time.
+export async function getLatestMajorVersion(
+  http: httpm.HttpClient
+): Promise<number> {
+  const availableReleasesUrl =
+    'https://api.adoptium.net/v3/info/available_releases';
+
+  const response =
+    await http.getJson<IAdoptiumAvailableReleases>(availableReleasesUrl);
+
+  const mostRecent = response.result?.most_recent_feature_release;
+  if (!mostRecent || Number.isNaN(Number(mostRecent))) {
+    throw new Error(
+      `Could not determine the latest available Java major version from ${availableReleasesUrl}`
+    );
+  }
+
+  return Number(mostRecent);
+}

tsconfig.json

@@ -2,8 +2,8 @@
   "compilerOptions": {
     /* Basic Options */
     // "incremental": true,                   /* Enable incremental compilation */
-    "target": "es6",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
+    "target": "ES2022",                        /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
-    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
+    "module": "NodeNext",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
     // "allowJs": true,                       /* Allow javascript files to be compiled. */
     // "checkJs": true,                       /* Report errors in .js files. */
     "resolveJsonModule": true,
@@ -61,5 +61,5 @@
     // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
     // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
   },
-  "exclude": ["node_modules", "**/*.test.ts"]
+  "exclude": ["node_modules", "**/*.test.ts", "jest.config.ts"]
 }