For a mono-repo setup I find Bazel much better than those two. If you have few hundred projects or more, Maven is a pretty bad choice. Gradle is slightly better

For a mono-repo setup I find Bazel much better than those two. If you have few hundred projects or more, Maven is a pretty bad choice. Gradle is slightly better, but still much slower than Bazel. But it's not just speed, Bazel does do true CI: you make a change in a a lib and then you can immediately compile and run tests on anything that depends on that directly or indirectly. I have not been able to do that with Gradle, forget about Maven. Finally, if you use other languages, with shared artifact such as protobuf files, Bazel is simply amazing: change a proto file and recompile everything that depends on that on every language.