I made myself the work and created a very basic ClosedFeedbackLoop Example for java, for anyone that might want to try it out. It's old and has terrible documentation, but I also haven't touched it in quite some time. Either way, here it is:

https://github.com/RicardoMonteiroSimoes/ClosedLoopControlBl...

It contains several blocks,P,I,D,PID,PT1 and PT2, basically the ones that were teached to me