Discussion: what's the relationship between rules_jvm and rules_java? about rules_jvm HOT 1 CLOSED

All reasonable questions. Hopefully #214 helps to clarify the situation.

Some specific answers:

Do I use rules_java or rules_jvm? Is rules_jvm a replacement or complement to rules_java?

Complement - you should use rules_java wherever it makes sense. rules_jvm doesn't offer any replacement functionality, but offers some additional functionality (e.g. support for running checkstyle, and wrapper macros you may want to wrap around things like java_library to support grouping tests).

Is rules_java "officially" supported?

Yes.

Gazelle support: I saw Gazelle support in rules_jvm, does it only work with rules_jvm?

The Gazelle implementation mostly generates targets which use rules from rules_java, e.g. it will generate java_library and java_binary targets from rules_java. You can see here which rules it will generate - most are from rules_java, but rules_java's test runner only supports junit4 not junit5, so if you have junit5 tests, we will instead generate a rule from rules_jvm which supports junit5. If rules_java started supporting junit5 (and the other functionality of rules_jvm's testrunner), we'd probably delete the rules_jvm testrunner - we're not in the business of implementing things Just Because, everything in here has been implemented because it wasn't elsewhere, and it would be hard for us to add to rules_java.

What's the future of rules_jvm?

Several major companies depend on it, so it is likely to continue being maintained, and it accepts contributions. You can see the minimal maintenance promises of rulesets in bazel-contrib here. But no guarantees are made.

Will it keep up with bzlmod?

Yes, I believe rules_jvm currently fully supports bzlmod, and tests this in CI.

from rules_jvm.