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

Unless I'm missing something, isn't the main difference between JNA vs JNI that with JNA you can't call Java code from native (C) code?

Answer 2

1. You are writing code a few years ago before there was JNA or are targeting a pre 1.4 JRE.
2. The code you are working with is not in a DLL\SO.
3. You are working on code that is incompatible with LGPL.

That is only what I can come up with off the top of my head, though I am not a heavy user of either. It also seems like you might avoid JNA if you wanted a better interface than the one they provide but you could code around that in java.

Answer 3

It's not a direct answer and I have no experience with JNA but, when I look at the Projects Using JNA and see names like SVNKit, IntelliJ IDEA, NetBeans IDE, etc, I'm tend to believe it's a pretty decent library.

Actually, I definitely think I would have used JNA instead of JNI when I had to as it indeed looks simpler than JNI (which has a boring development process). Too bad, JNA wasn't released at this time.

Answer 4

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).