Thread: JNI - UnsatisfiedLinkError

I've always been interested in learning more about JNI, but I appear to be stuck just getting started. I have read through several tutorials and decided to start with a simple Hello World JNI program just to get my feet wet. Unfortunately, I can't seem to get past the UnsatisfiedLink Error while running my program. Here is the code:

Hello.java

public class Hello{
    public native void sayHello();
 
    static{
        System.loadLibrary("hello");
    }
 
    public static void main(String[] args){
        Hello h = new Hello();
        h.sayHello();
    }
}

I compiled the above with javac Hello.java, then ran javah Hello to create the following:

Hello.h

/* 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:    sayHello
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_Hello_sayHello
  (JNIEnv *, jobject);
 
#ifdef __cplusplus
}
#endif
#endif

I then wrote Hello.c

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

I compiled this on my Ubuntu machine with the following command:

gcc -I"/usr/lib/jvm/java-6-openjdk/include" -I"/usr/lib/jvm/java-6-openjdk/include/linux" Hello.c -o libHello.so

I've also tried the above with -shared, -fPIC, and a slew of other flags trying to find the magic compilation command that gets the program to run.

When I try to run my program with

java -Djava.library.path='pwd' Hello
OR
java -Djava.library.path=. Hello
OR Simply
java Hello

I always get the following error:

Exception in thread "main" java.lang.UnsatisfiedLinkError: no hello in java.library.path
	at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1681)
	at java.lang.Runtime.loadLibrary0(Runtime.java:840)
	at java.lang.System.loadLibrary(System.java:1047)
	at Hello.<clinit>(Hello.java:5)
Could not find the main class: Hello. Program will exit.

My Google skills don't seem to be up to finding a solution that works on my system. Can anyone shed any light on what I'm doing wrong?

Thanks for spending time looking at this.