diff --git a/__tests__/setup-java.test.ts b/__tests__/setup-java.test.ts
new file mode 100644
index 00000000..58785ccc
--- /dev/null
+++ b/__tests__/setup-java.test.ts
@@ -0,0 +1,409 @@
+import {jest, describe, it, expect, beforeEach} from '@jest/globals';
+
+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((value: string) => value),
+  toWin32Path: jest.fn((value: string) => value),
+  toPosixPath: jest.fn((value: string) => value)
+}));
+
+jest.unstable_mockModule('fs', () => ({
+  default: {
+    readFileSync: jest.fn()
+  }
+}));
+
+jest.unstable_mockModule('../src/util.js', () => ({
+  getBooleanInput: jest.fn(),
+  isCacheFeatureAvailable: jest.fn(),
+  getVersionFromFileContent: jest.fn()
+}));
+
+jest.unstable_mockModule('../src/toolchains.js', () => ({
+  validateToolchainIds: jest.fn(),
+  configureToolchains: jest.fn()
+}));
+
+jest.unstable_mockModule('../src/cache.js', () => ({
+  restore: jest.fn()
+}));
+
+jest.unstable_mockModule(
+  '../src/distributions/distribution-factory.js',
+  () => ({
+    getJavaDistribution: jest.fn()
+  })
+);
+
+jest.unstable_mockModule('../src/auth.js', () => ({
+  configureAuthentication: jest.fn()
+}));
+
+jest.unstable_mockModule('../src/maven-args.js', () => ({
+  configureMavenArgs: jest.fn()
+}));
+
+jest.unstable_mockModule('../src/problem-matcher.js', () => ({
+  configureProblemMatcher: jest.fn()
+}));
+
+const core = await import('@actions/core');
+const fs = (await import('fs')).default;
+const util = await import('../src/util.js');
+const toolchains = await import('../src/toolchains.js');
+const cache = await import('../src/cache.js');
+const factory = await import('../src/distributions/distribution-factory.js');
+const auth = await import('../src/auth.js');
+const mavenArgs = await import('../src/maven-args.js');
+const problemMatcher = await import('../src/problem-matcher.js');
+const {run} = await import('../src/setup-java.js');
+
+const inputCallsOnImport = (core.getInput as jest.Mock).mock.calls.length;
+const multilineInputCallsOnImport = (core.getMultilineInput as jest.Mock).mock
+  .calls.length;
+
+describe('setup action orchestration', () => {
+  const inputs = new Map<string, string>();
+  const multilineInputs = new Map<string, string[]>();
+  const booleanInputs = new Map<string, boolean>();
+
+  beforeEach(() => {
+    jest.resetAllMocks();
+    inputs.clear();
+    multilineInputs.clear();
+    booleanInputs.clear();
+
+    (core.getInput as jest.Mock).mockImplementation((name: unknown) => {
+      return inputs.get(name as string) ?? '';
+    });
+    (core.getMultilineInput as jest.Mock).mockImplementation(
+      (name: unknown) => {
+        return multilineInputs.get(name as string) ?? [];
+      }
+    );
+    (util.getBooleanInput as jest.Mock).mockImplementation(
+      (name: unknown, defaultValue: unknown) => {
+        return booleanInputs.get(name as string) ?? defaultValue;
+      }
+    );
+    (util.isCacheFeatureAvailable as jest.Mock).mockReturnValue(true);
+    (toolchains.configureToolchains as jest.Mock).mockResolvedValue(undefined);
+    (auth.configureAuthentication as jest.Mock).mockResolvedValue(undefined);
+    (cache.restore as jest.Mock).mockResolvedValue(undefined);
+  });
+
+  it('does not execute the action when imported', () => {
+    expect(inputCallsOnImport).toBe(0);
+    expect(multilineInputCallsOnImport).toBe(0);
+  });
+
+  it('requires java-version or java-version-file', async () => {
+    await run();
+
+    expect(core.setFailed).toHaveBeenCalledWith(
+      'java-version or java-version-file input expected'
+    );
+    expect(factory.getJavaDistribution).not.toHaveBeenCalled();
+    expect(problemMatcher.configureProblemMatcher).not.toHaveBeenCalled();
+  });
+
+  it('requires distribution when java-version is provided', async () => {
+    multilineInputs.set('java-version', ['21']);
+
+    await run();
+
+    expect(core.setFailed).toHaveBeenCalledWith(
+      'distribution input is required'
+    );
+    expect(factory.getJavaDistribution).not.toHaveBeenCalled();
+  });
+
+  it('requires distribution when it cannot be inferred from the version file', async () => {
+    inputs.set('java-version-file', '.java-version');
+    (fs.readFileSync as jest.Mock).mockReturnValue(Buffer.from('21'));
+    (util.getVersionFromFileContent as jest.Mock).mockReturnValue({
+      version: '21'
+    });
+
+    await run();
+
+    expect(core.setFailed).toHaveBeenCalledWith(
+      'distribution input is required when not specified in the version file'
+    );
+    expect(factory.getJavaDistribution).not.toHaveBeenCalled();
+  });
+
+  it('fails when the version file has no supported version', async () => {
+    inputs.set('java-version-file', '.java-version');
+    inputs.set('distribution', 'temurin');
+    (fs.readFileSync as jest.Mock).mockReturnValue(Buffer.from('invalid'));
+    (util.getVersionFromFileContent as jest.Mock).mockReturnValue(undefined);
+
+    await run();
+
+    expect(core.setFailed).toHaveBeenCalledWith(
+      'No supported version was found in file .java-version'
+    );
+    expect(factory.getJavaDistribution).not.toHaveBeenCalled();
+  });
+
+  it('uses the distribution inferred from a version file', async () => {
+    inputs.set('java-version-file', '.sdkmanrc');
+    inputs.set('architecture', 'x64');
+    inputs.set('java-package', 'jdk');
+    inputs.set('distribution', 'zulu');
+    inputs.set('jdk-file', '/tmp/java.tar.gz');
+    multilineInputs.set('mvn-toolchain-id', ['file-jdk']);
+    booleanInputs.set('check-latest', true);
+    booleanInputs.set('force-download', true);
+    booleanInputs.set('set-default', false);
+    booleanInputs.set('verify-signature', true);
+    inputs.set('verify-signature-public-key', 'public-key');
+    (fs.readFileSync as jest.Mock).mockReturnValue(
+      Buffer.from('java=21.0.5-tem')
+    );
+    (util.getVersionFromFileContent as jest.Mock).mockReturnValue({
+      version: '21.0.5',
+      distribution: 'temurin'
+    });
+    const setupJava = jest.fn(async () => ({
+      version: '21.0.5+11',
+      path: '/opt/java/21'
+    }));
+    (factory.getJavaDistribution as jest.Mock).mockReturnValue({setupJava});
+
+    await run();
+
+    expect(util.getVersionFromFileContent).toHaveBeenCalledWith(
+      'java=21.0.5-tem',
+      'zulu',
+      '.sdkmanrc'
+    );
+    expect(factory.getJavaDistribution).toHaveBeenCalledWith(
+      'temurin',
+      {
+        version: '21.0.5',
+        architecture: 'x64',
+        packageType: 'jdk',
+        checkLatest: true,
+        forceDownload: true,
+        setDefault: false,
+        verifySignature: true,
+        verifySignaturePublicKey: 'public-key'
+      },
+      '/tmp/java.tar.gz'
+    );
+    expect(toolchains.validateToolchainIds).toHaveBeenCalledWith(
+      [],
+      '.sdkmanrc',
+      ['file-jdk']
+    );
+    expect(toolchains.configureToolchains).toHaveBeenCalledWith(
+      '21.0.5',
+      'temurin',
+      '/opt/java/21',
+      'file-jdk'
+    );
+    expect(core.setFailed).not.toHaveBeenCalled();
+  });
+
+  it('installs multiple JDKs in order with matching toolchain IDs', async () => {
+    inputs.set('distribution', 'temurin');
+    inputs.set('architecture', 'x64');
+    inputs.set('java-package', 'jdk');
+    multilineInputs.set('java-version', ['17', '21']);
+    multilineInputs.set('mvn-toolchain-id', ['java-17', 'java-21']);
+
+    const setupJava17 = jest.fn(async () => ({
+      version: '17.0.12+7',
+      path: '/opt/java/17'
+    }));
+    const setupJava21 = jest.fn(async () => ({
+      version: '21.0.4+7',
+      path: '/opt/java/21'
+    }));
+    (factory.getJavaDistribution as jest.Mock)
+      .mockReturnValueOnce({setupJava: setupJava17})
+      .mockReturnValueOnce({setupJava: setupJava21});
+
+    await run();
+
+    expect(factory.getJavaDistribution).toHaveBeenNthCalledWith(
+      1,
+      'temurin',
+      expect.objectContaining({version: '17'}),
+      ''
+    );
+    expect(factory.getJavaDistribution).toHaveBeenNthCalledWith(
+      2,
+      'temurin',
+      expect.objectContaining({version: '21'}),
+      ''
+    );
+    expect(toolchains.configureToolchains).toHaveBeenNthCalledWith(
+      1,
+      '17',
+      'temurin',
+      '/opt/java/17',
+      'java-17'
+    );
+    expect(toolchains.configureToolchains).toHaveBeenNthCalledWith(
+      2,
+      '21',
+      'temurin',
+      '/opt/java/21',
+      'java-21'
+    );
+    expect(setupJava17.mock.invocationCallOrder[0]).toBeLessThan(
+      setupJava21.mock.invocationCallOrder[0]
+    );
+  });
+
+  it('uses the resolved version for the latest Maven toolchain', async () => {
+    inputs.set('distribution', 'temurin');
+    multilineInputs.set('java-version', ['latest']);
+    const setupJava = jest.fn(async () => ({
+      version: '24.0.2+12',
+      path: '/opt/java/24'
+    }));
+    (factory.getJavaDistribution as jest.Mock).mockReturnValue({setupJava});
+
+    await run();
+
+    expect(toolchains.configureToolchains).toHaveBeenCalledWith(
+      '24.0.2+12',
+      'temurin',
+      '/opt/java/24',
+      undefined
+    );
+  });
+
+  it('configures post-install collaborators in order and restores the cache last', async () => {
+    inputs.set('distribution', 'temurin');
+    inputs.set('cache', 'maven');
+    inputs.set('cache-dependency-path', '**/pom.xml');
+    multilineInputs.set('java-version', ['21']);
+    const setupJava = jest.fn(async () => ({
+      version: '21.0.4+7',
+      path: '/opt/java/21'
+    }));
+    (factory.getJavaDistribution as jest.Mock).mockReturnValue({setupJava});
+
+    await run();
+
+    expect(problemMatcher.configureProblemMatcher).toHaveBeenCalledWith(
+      expect.stringMatching(/\.github[/\\]java\.json$/)
+    );
+    expect(cache.restore).toHaveBeenCalledWith('maven', '**/pom.xml');
+    expect(
+      (toolchains.configureToolchains as jest.Mock).mock.invocationCallOrder[0]
+    ).toBeLessThan(
+      (problemMatcher.configureProblemMatcher as jest.Mock).mock
+        .invocationCallOrder[0]
+    );
+    expect(
+      (problemMatcher.configureProblemMatcher as jest.Mock).mock
+        .invocationCallOrder[0]
+    ).toBeLessThan(
+      (auth.configureAuthentication as jest.Mock).mock.invocationCallOrder[0]
+    );
+    expect(
+      (auth.configureAuthentication as jest.Mock).mock.invocationCallOrder[0]
+    ).toBeLessThan(
+      (mavenArgs.configureMavenArgs as jest.Mock).mock.invocationCallOrder[0]
+    );
+    expect(
+      (mavenArgs.configureMavenArgs as jest.Mock).mock.invocationCallOrder[0]
+    ).toBeLessThan((cache.restore as jest.Mock).mock.invocationCallOrder[0]);
+  });
+
+  it('skips cache restoration when the cache feature is unavailable', async () => {
+    inputs.set('distribution', 'temurin');
+    inputs.set('cache', 'maven');
+    multilineInputs.set('java-version', ['21']);
+    (util.isCacheFeatureAvailable as jest.Mock).mockReturnValue(false);
+    (factory.getJavaDistribution as jest.Mock).mockReturnValue({
+      setupJava: jest.fn(async () => ({
+        version: '21.0.4+7',
+        path: '/opt/java/21'
+      }))
+    });
+
+    await run();
+
+    expect(cache.restore).not.toHaveBeenCalled();
+  });
+
+  it('reports unsupported distributions through core.setFailed', async () => {
+    inputs.set('distribution', 'unsupported');
+    multilineInputs.set('java-version', ['21']);
+    (factory.getJavaDistribution as jest.Mock).mockReturnValue(null);
+
+    await run();
+
+    expect(core.setFailed).toHaveBeenCalledWith(
+      'No supported distribution was found for input unsupported'
+    );
+    expect(toolchains.configureToolchains).not.toHaveBeenCalled();
+    expect(problemMatcher.configureProblemMatcher).not.toHaveBeenCalled();
+  });
+
+  it('reports collaborator failures and stops post-install configuration', async () => {
+    inputs.set('distribution', 'temurin');
+    multilineInputs.set('java-version', ['21']);
+    (factory.getJavaDistribution as jest.Mock).mockReturnValue({
+      setupJava: jest.fn(async () => {
+        throw new Error('download failed');
+      })
+    });
+
+    await run();
+
+    expect(core.setFailed).toHaveBeenCalledWith('download failed');
+    expect(toolchains.configureToolchains).not.toHaveBeenCalled();
+    expect(problemMatcher.configureProblemMatcher).not.toHaveBeenCalled();
+    expect(auth.configureAuthentication).not.toHaveBeenCalled();
+    expect(mavenArgs.configureMavenArgs).not.toHaveBeenCalled();
+    expect(cache.restore).not.toHaveBeenCalled();
+  });
+
+  it('reports post-install failures and skips later collaborators', async () => {
+    inputs.set('distribution', 'temurin');
+    inputs.set('cache', 'maven');
+    multilineInputs.set('java-version', ['21']);
+    (factory.getJavaDistribution as jest.Mock).mockReturnValue({
+      setupJava: jest.fn(async () => ({
+        version: '21.0.4+7',
+        path: '/opt/java/21'
+      }))
+    });
+    (auth.configureAuthentication as jest.Mock).mockRejectedValue(
+      new Error('authentication failed')
+    );
+
+    await run();
+
+    expect(problemMatcher.configureProblemMatcher).toHaveBeenCalled();
+    expect(core.setFailed).toHaveBeenCalledWith('authentication failed');
+    expect(mavenArgs.configureMavenArgs).not.toHaveBeenCalled();
+    expect(cache.restore).not.toHaveBeenCalled();
+  });
+});
diff --git a/dist/setup/index.js b/dist/setup/index.js
index 0dcc3972..7f15ff1a 100644
--- a/dist/setup/index.js
+++ b/dist/setup/index.js
@@ -68941,6 +68941,11 @@ module.exports = /*#__PURE__*/JSON.parse('{"name":"@actions/cache","version":"6.
 /************************************************************************/
 var __webpack_exports__ = {};
 
+// EXPORTS
+__nccwpck_require__.d(__webpack_exports__, {
+  e: () => (/* binding */ run)
+});
+
 // NAMESPACE OBJECT: ./node_modules/@azure/storage-blob/dist/esm/generated/src/models/mappers.js
 var mappers_namespaceObject = {};
 __nccwpck_require__.r(mappers_namespaceObject);
@@ -132361,7 +132366,13 @@ async function run() {
         setFailed(error.message);
     }
 }
-run();
+if (process.argv[1] === (0,external_url_.fileURLToPath)(import.meta.url)) {
+    run();
+}
+else {
+    // https://nodejs.org/api/modules.html#modules_accessing_the_main_module
+    info('the script is loaded as a module, so skipping the execution');
+}
 function getJdkFileInput() {
     const jdkFile = getInput(INPUT_JDK_FILE);
     const deprecatedJdkFile = getInput(INPUT_JDK_FILE_DEPRECATED);
@@ -132400,3 +132411,5 @@ async function installVersion(version, options, toolchainId = 0) {
     info('');
 }
 
+var __webpack_exports__run = __webpack_exports__.e;
+export { __webpack_exports__run as run };
diff --git a/src/setup-java.ts b/src/setup-java.ts
index 5bfe084f..8945ede3 100644
--- a/src/setup-java.ts
+++ b/src/setup-java.ts
@@ -16,7 +16,7 @@ import {JavaInstallerOptions} from './distributions/base-models.js';
 import {configureMavenArgs} from './maven-args.js';
 import {configureProblemMatcher} from './problem-matcher.js';
 
-async function run() {
+export async function run() {
   try {
     const versions = core.getMultilineInput(constants.INPUT_JAVA_VERSION);
     let distributionName = core.getInput(constants.INPUT_DISTRIBUTION);
@@ -139,7 +139,12 @@ async function run() {
   }
 }
 
-run();
+if (process.argv[1] === fileURLToPath(import.meta.url)) {
+  run();
+} else {
+  // https://nodejs.org/api/modules.html#modules_accessing_the_main_module
+  core.info('the script is loaded as a module, so skipping the execution');
+}
 
 function getJdkFileInput(): string {
   const jdkFile = core.getInput(constants.INPUT_JDK_FILE);