How to compile Java native library?

You can create shared object file using below mentioned command.

gcc -shared -fpic -o <so-file-name>.so a.c b.c 

on Mac OS X, compile with:

g++ -dynamiclib -flat_namespace myclass.cc -o myclass.so g++ class_user.cc -o class_user 

On Linux, compile with:

g++ -fPIC -shared myclass.cc -o myclass.so g++ class_user.cc -ldl -o class_user 

References:

C++ Dynamic Shared Library on Linux

Build .so file from .c file using gcc command line

Sample tutorial

Sample code to run .so file using java with commands:

HelloJNI.c

#include <jni.h> #include <stdio.h> #include "HelloJNI.h" JNIEXPORT void JNICALL Java_HelloJNI_sayHello(JNIEnv *env, jobject thisObj) { printf("Hello World!\n"); return; } 

HelloJNI.java

public class HelloJNI { static { System.loadLibrary("hello"); // hello.dll (Windows) or libhello.so (Unixes) } // A native method that receives nothing and returns void private native void sayHello(); public static void main(String[] args) { new HelloJNI().sayHello(); // invoke the native method } } 

Steps to run above .c file using .java file

javac HelloJNI javah HelloJNI gcc -shared -fpic -o libhello.so -I/usr/java/default/include -I/usr/java/default/include/linux HelloJNI.c java -Djava.library.path=. HelloJNI