Error trying to run gradlew setupDecompWorkspace

[Tyses96]

So just trying to setup forge and I get this error:

 

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine java version from '12.0.2'.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

 

So I've read about it could be the gradle version not being compatible with java, or forge not being compatible with the java version, but no where have I seen anyone posting a Solution. 

I'd like to know 

1)What the Isuue is.
2)What the solution is and how to implement it.

Thanks:)

[Tyses96]

Thank you very much.

I will downgrade:)