No one has suggested 68k assembly.
There are two ways you could approach it: A tutorial language where you learn the structure of programs.
Otherway would be a low level language 68k or C (both are similiar) using the Amiga libraries if you are familiar with them.
Learning Java or C is hard and you won't be doing interesting programs for a while.
Java has different versions which are not compatible. I'm pretty sure C++ has stayed the same.
