Building LO java extension with Gradle or Ant

Hi all,

I'm working on a LO java extension. Examples in LO SDK use Makefiles,
while in Java dev there are other build tools commonly used, such as
Gradle, Maven and Ant.

I'm looking for a script to build LO extension with those tools,
preferable Gradle because it's builtin into IntelliJ Idea which I'm
using. Ant script would do too.

I found a Maven script in languagetool extension, but I do not know
maven well enough, and languagetool build script is quite complex.
Something simpler would be better ))

Any info on Gradle or Ant scripts samples to build LO Java extension
is appreciated.

Thanks,
Mike