My advice would be to use Sikuli, because it is independent from Java. See the Sikuli Robot Framework Library | robotframework-SikuliLibrary and do a small PoC.
It would be good to try SikuliX first, to be familiar with the workflow. New version allows to use Robot Framework from its IDE.
The problem with libraries for Java is that they are based on Jython (based on Python 2.7), so they are outdated.
These are two that I know of: