Choose class to execute by giving classname in variable

I have let's say "Merge-Classes" that I call when I need to merge specific data with a specific JasperReport (Template). For each of those reports I need its own class to merge the data. I fill this reports dynamicaly, depending on which my custom wants.

Is it possible that I give my programm the name of the class and the method to call by a variable String and call that class/method? So it would be easy to add new Merge-Classes to my program (only copy paste the file and call by given name)