About JNI

Question

Hi,
I am new to JNI programming. I tested the following hello world programm:
HelloWorld.java:
class HelloWorld {
public native void displayHelloWorld();
static {
System.loadLibrary("HelloWorld");
public static void main(String[] args) {
new HelloWorld().displayHelloWorld();
HelloWorld.cpp:
#include <jni.h>
#include "HelloWorld.h"
#include <stdio.h>
JNIEXPORT void JNICALL
Java_HelloWorld_displayHelloWorld(JNIEnv *env, jobject obj)
printf("Hello world!\n");
return;
I compiled the C++ code with Visual C++ 6.0, I created de project with the opcion "MFC AppWizard (dll)"
and when I compiled the code with C++ I have an error "fatal error C1083: cannot open include file: �jni.h�: no such file or directory
error executing cl.exe"
I mean the c++ code was not compiled and when I did java HelloWord I had the follow error:
Exception in thread "main" java.lang.UnsatisfiedLinkError: displayHelloWord
     at HelloWorld().displayHelloWorld(Native Method)
     at HelloWorld().main(HelloWorld.java)
I have no idea what this mean
Anyone have an idea? please help me
Thank you in advance.

Answer 1

Hi
I could compile the file C++ and I tried to run the file HolaMundo.java but I have the follow error
C:\Documents and Settings\yamilet\Mis documentos\prueba\intento>java -Djava.libr
ary.path=. HolaMundo
Exception in thread "main" java.lang.UnsatisfiedLinkError: no HolaMundo in java.
library.path
at java.lang.ClassLoader.loadLibrary(Unknown Source)
at java.lang.Runtime.loadLibrary0(Unknown Source)
at java.lang.System.loadLibrary(Unknown Source)
at HolaMundo.<clinit>(HolaMundo.java:9)
C:\Documents and Settings\yamilet\Mis documentos\prueba\intento>
I have the files HolaMundo.h and HolaMundo.java inside the directory Hola.
The directory Hola had the C++'project and the file HolaMundo.dll was inside the Debuc'folder
and Debuc'folder was automatic generate for the C++'compiler.
I mean The loadLibrary isn't work, I mean the java'compiler don't know where is the file HolaMundo
I tried to put it inside the directory Debug but I still the error.
I tried to put it inside the directory hola but I still the error.
The file HolaMundo.java is
public class HolaMundo
     private native void saluda();
     public static void main(String[] args)
     new HolaMundo().saluda();
     static
     System.loadLibrary("HolaMundo");
HolaMundo is the file .dll and it is inside the directory Debug
Have you any idea? Please help me
Thank for advance.