Use JNI instead of JNA to call native code?

Question

JNA seems a fair bit easier to use to call native code compared to JNI. In what cases would you use JNI over JNA?

Answer 1

By the way, in one of our projects, we kept a very small JNI foot print. We used protocol buffers for representing our domain objects and thus had only one native function to bridge Java and C (then of course that C function would call a bunch of other functions).