How to use Java Objects with UI Designer

I have a very simple Java class with two Integer variables and their getters and setters.
Nothing special. My goal is a Set Data task to take two numbers for a and b (from the form) and the next task Get Data to print in the form, using class functions. I want this through setters and getters. I just cannot find an example with newer Bonita versions (in the previous versions was too easy to do something like that) about Java objects and UI Designer.

In the end, I just desperately need a tutorial about java objects + ui designer and there isn't one for newer version.