# setup-java

<p align="left">
  <a href="https://github.com/actions/setup-java"><img alt="GitHub Actions status" src="https://github.com/actions/setup-java/workflows/Main%20workflow/badge.svg"></a>
</p>

This action provides the following functionality for GitHub Actions runners:
- Downloading and setting up a requested version of Java. See [Usage](#Usage) for a list of supported distributions
- Extracting and caching custom version of Java from a local file
- Configuring runner for publishing using Apache Maven
- Configuring runner for publishing using Gradle
- Configuring runner for using GPG private key
- Registering problem matchers for error output
- Caching dependencies managed by Apache Maven
- Caching dependencies managed by Gradle

## V2 vs V1
- V2 supports custom distributions and provides support for Zulu OpenJDK, Eclipse Temurin and Adopt OpenJDK  out of the box. V1 supports only Zulu OpenJDK
- V2 requires you to specify distribution along with the version. V1 defaults to Zulu OpenJDK, only version input is required. Follow [the migration guide](docs/switching-to-v2.md) to switch from V1 to V2

## Usage
Inputs `java-version` and `distribution` are mandatory. See [Supported distributions](#supported-distributions) section for a list of available options.

### Basic
**Eclipse Temurin**
```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-java@v2
  with:
    distribution: 'temurin' # See 'Supported distributions' for available options
    java-version: '17'
- run: java -cp java HelloWorldApp
```

**Zulu OpenJDK**
```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-java@v2
  with:
    distribution: 'zulu' # See 'Supported distributions' for available options
    java-version: '11'
- run: java -cp java HelloWorldApp
```

#### Supported version syntax
The `java-version` input supports an exact version or a version range using [SemVer](https://semver.org/) notation:
- major versions: `8`, `11`, `16`, `17`
- more specific versions: `17.0`, `11.0`, `11.0.4`, `8.0.232`, `8.0.282+8`
- early access (EA) versions: `15-ea`, `15.0.0-ea`, `15.0.0-ea.2`, `15.0.0+2-ea`

#### Supported distributions
Currently, the following distributions are supported:
| Keyword | Distribution | Official site | License
|-|-|-|-|
| `temurin` | Eclipse Temurin | [Link](https://adoptium.net/) | [Link](https://adoptium.net/about.html)
| `zulu` | Zulu OpenJDK | [Link](https://www.azul.com/downloads/zulu-community/?package=jdk) | [Link](https://www.azul.com/products/zulu-and-zulu-enterprise/zulu-terms-of-use/) |
| `adopt` or `adopt-hotspot` | Adopt OpenJDK Hotspot | [Link](https://adoptopenjdk.net/) | [Link](https://adoptopenjdk.net/about.html) |
| `adopt-openj9` | Adopt OpenJDK OpenJ9 | [Link](https://adoptopenjdk.net/) | [Link](https://adoptopenjdk.net/about.html) |
| `liberica` | Liberica JDK | [Link](https://bell-sw.com/) | [Link](https://bell-sw.com/liberica_eula/) |
| `microsoft` | Microsoft Build of OpenJDK | [Link](https://www.microsoft.com/openjdk) | [Link](https://docs.microsoft.com/java/openjdk/faq)

**NOTE:** The different distributors can provide discrepant list of available versions / supported configurations. Please refer to the official documentation to see the list of supported versions.

**NOTE:** Adopt OpenJDK got moved to Eclipse Temurin and won't be updated anymore. It is highly recommended to migrate workflows from `adopt` to `temurin` to keep receiving software and security updates. See more details in the [Good-bye AdoptOpenJDK post](https://blog.adoptopenjdk.net/2021/08/goodbye-adoptopenjdk-hello-adoptium/).

### Caching packages dependencies
The action has a built-in functionality for caching and restoring dependencies. It uses [actions/cache](https://github.com/actions/cache) under hood for caching dependencies but requires less configuration settings. Supported package managers are gradle and maven. The cache input is optional, and caching is turned off by default.

The option to use the cache in a read-only mode is available via the parameter `cache-is-read-only`, which
defaults to `false`. When set to `true`, and caching is enabled, this allows PR workflows to benefit from 
cached build artifacts, but not taint the cache with PR specific changes which may be in a state of flux.

#### Caching gradle dependencies
```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-java@v2
  with:
    distribution: 'temurin'
    java-version: '11'
    cache: 'gradle'
- run: ./gradlew build --no-daemon
```

#### Caching maven dependencies
```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-java@v2
  with:
    distribution: 'temurin'
    java-version: '11'
    cache: 'maven'
- name: Build with Maven
  run: mvn -B package --file pom.xml
```

### Check latest
In the basic examples above, the `check-latest` flag defaults to `false`. When set to `false`, the action tries to first resolve a version of Java from the local tool cache on the runner. If unable to find a specific version in the cache, the action will download a version of Java. Use the default or set `check-latest` to `false` if you prefer a faster more consistent setup experience that prioritizes trying to use the cached versions at the expense of newer versions sometimes being available for download.

If `check-latest` is set to `true`, the action first checks if the cached version is the latest one. If the locally cached version is not the most up-to-date, the latest version of Java will be downloaded. Set `check-latest` to `true` if you want the most up-to-date version of Java to always be used. Setting `check-latest` to `true` has performance implications as downloading versions of Java is slower than using cached versions.

For Java distributions that are not cached on Hosted images, `check-latest` always behaves as `true` and downloads Java on-flight. Check out [Hosted Tool Cache](docs/advanced-usage.md#Hosted-Tool-Cache) for more details about pre-cached Java versions.  


```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-java@v2
  with:
    distribution: 'adopt'
    java-version: '11'
    check-latest: true
- run: java -cp java HelloWorldApp
```

### Testing against different Java versions
```yaml
jobs:
  build:
    runs-on: ubuntu-20.04
    strategy:
      matrix:
        java: [ '8', '11', '13', '15' ]
    name: Java ${{ matrix.Java }} sample
    steps:
      - uses: actions/checkout@v2
      - name: Setup java
        uses: actions/setup-java@v2
        with:
          distribution: '<distribution>'
          java-version: ${{ matrix.java }}
      - run: java -cp java HelloWorldApp
```

### Advanced
- [Selecting a Java distribution](docs/advanced-usage.md#Selecting-a-Java-distribution)
  - [Eclipse Temurin](docs/advanced-usage.md#Eclipse-Temurin)
  - [Adopt](docs/advanced-usage.md#Adopt)
  - [Zulu](docs/advanced-usage.md#Zulu)
  - [Liberica](docs/advanced-usage.md#Liberica)
- [Installing custom Java package type](docs/advanced-usage.md#Installing-custom-Java-package-type)
- [Installing custom Java architecture](docs/advanced-usage.md#Installing-custom-Java-architecture)
- [Installing custom Java distribution from local file](docs/advanced-usage.md#Installing-Java-from-local-file)
- [Testing against different Java distributions](docs/advanced-usage.md#Testing-against-different-Java-distributions)
- [Testing against different platforms](docs/advanced-usage.md#Testing-against-different-platforms)
- [Publishing using Apache Maven](docs/advanced-usage.md#Publishing-using-Apache-Maven)
- [Publishing using Gradle](docs/advanced-usage.md#Publishing-using-Gradle)
- [Hosted Tool Cache](docs/advanced-usage.md#Hosted-Tool-Cache)

## License

The scripts and documentation in this project are released under the [MIT License](LICENSE).

## Contributions

Contributions are welcome! See [Contributor's Guide](CONTRIBUTING.md)