How to call C++ from Java?

While I've used JNI-C++ bridging in the past (only a little though) - it can be a bit ugly. You might want to consider using SWIG to help you generate all the messy boiler plate code.

If JNI is too complicated you can take a look at JNA. In first case you have to create native wrapper code (in C or C++) to join Java and native (C++/C/...) code. In second case it is done at runtime (so you only need Java code + config).

I use JNR/FFI https://github.com/jnr/jnr-ffi which I have found to be faster than JNA and easier than SWIG. It's as close to JNI for speed I have found but less error prone.