Java bindings - Adding Atomic* support

Java bindings - Adding Atomic* support

AtomicIntegers are used to address some concurrency problems in Java, and this
is advised by some metrics libraries like Netflix's servo:

https://github.com/Netflix/servo/wiki#jmx

Unfortunately, the GenericJMXConfValue.java class is not able to get the values
from such types, hence this PR.

I scanned the Java doc for the Java package:
https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/atomic/package-summary.html
I think I have not forgotten any types.

Tests: tested at runtime