I took a look at the LLVM preset and it looked like you had to pass object handles to static functions. I'd prefer to have an actual, say, LLVM::Module equivalent object in Java that you can call member functions on. Are all the presets like this?
No, that's because in the specific case of LLVM only the C API is currently mapped. We'd have to work a little bit harder for the C++ API, but there is interest in doing so, if only to use it as a better parser for JavaCPP itself:
Improve Parser: Use the Clang API
https://github.com/bytedeco/javacpp/issues/51