- [Installing custom Java distribution from local file](#Installing-Java-from-local-file)
- [Testing against different Java distributions](#Testing-against-different-Java-distributions)
- [Testing against different platforms](#Testing-against-different-platforms)
- [Publishing using Apache Maven](#Publishing-using-Apache-Maven)
- [Publishing using Gradle](#Publishing-using-Gradle)
- [Hosted Tool Cache](#Hosted-Tool-Cache)
See [action.yml](../action.yml) for more details on task inputs.
## Selecting a Java distribution
Inputs `java-version` and `distribution` are mandatory and needs to be provided. See [Supported distributions](../README.md#Supported-distributions) for a list of available options.
**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/).
If your use-case requires a custom distribution or a version that is not provided by setup-java, you can download it manually and setup-java will take care of the installation and caching on the VM:
**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***: The `settings.xml` file is created in the Actions `$HOME/.m2` directory. If you have an existing `settings.xml` file at that location, it will be overwritten. See [below](#apache-maven-with-a-settings-path) for using the `settings-path` to change your `settings.xml` file location.
If you don't want to overwrite the `settings.xml` file, you can set `overwrite-settings: false`
### Extra setup for pom.xml:
The Maven GPG Plugin configuration in the pom.xml file should contain the following structure to avoid possible issues like `Inappropriate ioctl for device` or `gpg: signing failed: No such file or directory`:
```xml
<configuration>
<!-- Prevent gpg from using pinentry programs -->
<gpgArguments>
<arg>--pinentry-mode</arg>
<arg>loopback</arg>
</gpgArguments>
</configuration>
```
GPG 2.1 requires `--pinentry-mode` to be set to `loopback` in order to pick up the `gpg.passphrase` value defined in Maven `settings.xml`.
### GPG
If `gpg-private-key` input is provided, the private key will be written to a file in the runner's temp directory, the private key file will be imported into the GPG keychain, and then the file will be promptly removed before proceeding with the rest of the setup process. A cleanup step will remove the imported private key from the GPG keychain after the job completes regardless of the job status. This ensures that the private key is no longer accessible on self-hosted runners and cannot "leak" between jobs (hosted runners are always clean instances).
**GPG key should be exported by: `gpg --armor --export-secret-keys YOUR_ID`**
See the help docs on [Publishing a Package](https://help.github.com/en/github/managing-packages-with-github-packages/configuring-apache-maven-for-use-with-github-packages#publishing-a-package) for more information on the `pom.xml` file.
When using an Actions self-hosted runner with multiple shared runners the default `$HOME` directory can be shared by a number runners at the same time which could overwrite existing settings file. Setting the `settings-path` variable allows you to choose a unique location for your settings file.
***NOTE: The `USERNAME` and `PASSWORD` need to correspond to the credentials environment variables used in the publishing section of your `build.gradle`.***
See the help docs on [Publishing a Package with Gradle](https://help.github.com/en/github/managing-packages-with-github-packages/configuring-gradle-for-use-with-github-packages#example-using-gradle-groovy-for-a-single-package-in-a-repository) for more information on the `build.gradle` configuration file.
GitHub Hosted Runners have a tool cache that comes with some Java versions pre-installed. This tool cache helps speed up runs and tool setup by not requiring any new downloads. There is an environment variable called `RUNNER_TOOL_CACHE` on each runner that describes the location of this tools cache and this is where you can find the pre-installed versions of Java. `setup-java` works by taking a specific version of Java in this tool cache and adding it to PATH if the version, architecture and distribution match.
The tools cache gets updated on a weekly basis. For information regarding locally cached versions of Java on GitHub hosted runners, check out [GitHub Actions Virtual Environments](https://github.com/actions/virtual-environments).
