- 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
Inputs `java-version` and `distribution` are mandatory. See [Supported distributions](#supported-distributions) section for a list of available options.
**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/).
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 format of the used cache key is `setup-java-${{ platform }}-${{ packageManager }}-${{ fileHash }}`, where the hash is based on the following files:
The workflow output `cache-hit` is set to indicate if an exact match was found for the key [as actions/cache does](https://github.com/actions/cache/tree/main#outputs).
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.
