Create and modified Pa (projectArea) by api java

I would need, if possible, to create and modify project areas using java bees. I found the source for the creation of the same, tried and works properly, but now I would also like to modify them, adding or removing ticket types or workflow states, but I can't find the way to do it in any way. I'm analyzing the projectArea object but I can't find useful references for what I'm looking for. Do you know if it is possible? Thanks.