I would check out Java Native Access (JNA) its a library that allow you to read and write to memory and if you know c++ it will not be that hard to start because they use the same names for objects and functions such as HWND and GetWindowRect but the bad part about making it in JAVA is that there is basically no code online that you can look at and try to learn from and you also need to write your own "procmem" which could be hard for some people but i totaly get you its a fun project that i tried too but scraped it to start on some other projects anyways good luck!