UnsatisfiedLinkError while calling C library from Java Programm

Question

Hi,
I am trying call C function from Java code but I am getting error.
Below is the code
package jnitest;
class HelloWorld {
    private native void print();
    public static void main(String[] args) {
        new HelloWorld().print();
    static {
        System.loadLibrary("HelloWorld");
}I used following commands to compile and generate header files
$ javac -d build src/jnitest/HelloWorld.java
$ javah -d build -classpath build -jni jnitest.HelloWorldThen jnitest_HelloWorld.h was generated and I renamed it to HelloWorld.h.
I implemented HelloWorld.h in HelloWorld.c.
Below is the code for both the files
HelloWorld.h
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class jnitest_HelloWorld */
#ifndef _Included_jnitest_HelloWorld
#define _Included_jnitest_HelloWorld
#ifdef __cplusplus
extern "C" {
#endif
* Class:     jnitest_HelloWorld
* Method:    print
* Signature: ()V
JNIEXPORT void JNICALL Java_jnitest_HelloWorld_print
  (JNIEnv *, jobject);
#ifdef __cplusplus
#endif
#endifHelloWorld.c
#include <jni.h>
#include <stdio.h>
#include "HelloWorld.h"
JNIEXPORT void JNICALL
Java_HelloWorld_print(JNIEnv *env, jobject obj)
  printf("Hello World!\n");
  return;
}I used following commands to generate so file
gcc -m32 -fPIC -D_REENTRANT -I/opt/jdk1.6.0_19/include -I/opt/jdk1.6.0_19/include/linux -c HelloWorld.c
gcc -m32 -shared HelloWorld.o -o libHelloWorld.soafter all the execution I get following directory struct in build directory
$ ls -R
HelloWorld.c  HelloWorld.h  jnitest  libHelloWorld.so
./jnitest:
HelloWorld.classI am executing following command to run the program.
build$ java -D. jnitest.HelloWorldbut I am getting exception
Exception in thread "main" java.lang.UnsatisfiedLinkError: jnitest.HelloWorld.print()V
     at jnitest.HelloWorld.print(Native Method)
     at jnitest.HelloWorld.main(HelloWorld.java:16)I pointed LD_LIBRARY_PATH to build directory and executed
java -classpath build jnitest.HelloWorldbut I am still getting the same error.
Please help to fix the issue.
Thanks,

Answer 1

The JNI method name in the .h file is different to that in the .c file.