I am sorry that I am bad at English(I am Dutch)
but a way around this is to run a external file like for example: like java cant restart your pc(yes it can but this is just a example) you can make java run a external file of C++ or another script language
yeah MCreator is very limited and I am not so good at public and private and static and that stuff I don't really know what static does and other stuff you can do with public and private
yeah I said that I will first learn the basics of java and after that try to make a very simple game(or simulation)