Question: Why this action needed?

[rchampa]

When I want to build, test, or bundle I just run ./gradlew task.
Why do i need to download java?

[missedone]

if you use github hosted runner, (aka runs-on: ubunut-latest), it has almost everything installed, check in details https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-README.md#android

however, on self-hosted runner, we may need this setp-android to have the android sdk setup to make build work

[vietanhduong]

It's true, if you're using self-hosted runner, so you need to install android on runner or use this action.