JNI tutorial for Mac OSx 10.9.4

JNI info

1. Install Eclipse IDE
2. Create new project
3. New class Hello.java (copy and paste code below)

public class Hello {

    public native int add(int a, int b);

    private native void sayHello();

   

   

    public static void main(String [] args) 

    {

    System.out.println(new Hello().add(34,50));

   

    new Hello().sayHello();

    }

    static {

    System.loadLibrary("hello");

    }

}

4. Open terminal. Go to file /dir. Enter below commands: 

    $javac Hello.java (compiles)

    $javah -jni -classpath . Hello

The above command generates your .h headers files from the Java.

5. Now create file "hello.c" copy and paste code below:

/* DO NOT EDIT THIS FILE - it is machine generated */

#include <jni.h>

/* Header for class Hello */

#ifndef _Included_Hello

#define _Included_Hello

#ifdef __cplusplus

extern "C" {

#endif

/*

 * Class:     Hello

 * Method:    add

 * Signature: (II)I

 */

JNIEXPORT jint JNICALL Java_Hello_add

  (JNIEnv *, jobject, jint, jint);

/*

 * Class:     Hello

 * Method:    sayHello

 * Signature: ()V

 */

JNIEXPORT void JNICALL Java_Hello_sayHello

  (JNIEnv *, jobject);

#ifdef __cplusplus

}

#endif

#endif

6. Now enter following commands

  $gcc -dynamiclib hello.c -I/System/Library/Frameworks/JavaVM.framework/Headers -o libhello.dylib

  $cp libhello.dylib /Library/Java//Extensions

  $java -cp . Hello

Output: 

84

Hello World!

Commands used (img):