JAVA and JNI
pre-requisite – Install Java SE Development Kit 6u14 under /usr/jdk1.6.0_14
1) Write a JAVA class [ HelloWorld.java ]
public class HelloWorld {
static {
System.loadLibrary(“hello”);
}
public native void printHelloWorld();
}
2) Compile the class using javac
sudo javac HelloWorld.java
after this HelloWorld.class file should get created.
3) Create header file required for writing a native program
sudo javah -jni HelloWorld
4) Write a helloworld.c native c program.
#include “HelloWorld.h”
#include <stdio.h>
JNIEXPORT void JNICALL
Java_HelloWorld_printHelloWorld (JNIEnv *env, jobject obj) {
printf(“Hello Worldn”);
}
5) Create a shared library.
gcc -I/usr/jdk1.6.0_14/include -I/usr/jdk1.6.0_14/include/linux -shared -o libhello.so HelloWorld.c
6) Write a Main java class[ Main.java ], which will call native function.
public class Main {
public static void main(String[] args) {
new HelloWorld().printHelloWorld();
}
}
7) Compile Main.java
javac Main.java
8) Run the program
java Main
Reference’s
1) Using the JAVA Native interface’s
2) JNI Example
3) Integrating Native methods into Java
5) http://java.sun.com/docs/books/jni/html/start.html