Error message that I don't understand

Question

hello guys
I have these programs in C++ and in Java that interact;
package Classes;
import java.io.*;
import java.lang.*;
import java.awt.*;
public class MyClass {
public native int WriteMessage(int c);
public void run(int mes){
mes=0;
WriteMessage(mes);
public static void main(String[] args)throws IOException {
int x;
int y=0;
String inputString = new String();
char Car;
MyClass m = new MyClass();
System.out.println("give x");
Car=(char)System.in.read();
while(Car >= '0' && Car <= '9'){
inputString = inputString + Car;
Car = (char)System.in.read();
x = Integer.parseInt(inputString);
y=m.WriteMessage(x);
System.out.println("new y:"+y);
and the C++ program is:
#include <jni.h>
#include "MyClass.h"
#include <iostream.h>
JNIEXPORT jint JNICALL
Java_MyClass_WriteMessage(JNIEnv *env, jobject obj, jint message){
cout<<"new message:"<<message;
message=message+10;
return message;
and it gives me this error message:
Exception in thread "main" java.lang.NoClassDefFoundError: MyClass (wrong name: Classes/MyClass)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:502)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:250)
at java.net.URLClassLoader.access$100(URLClassLoader.java:54)
at java.net.URLClassLoader$1.run(URLClassLoader.java:193)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:186)
at java.lang.ClassLoader.loadClass(ClassLoader.java:299)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:265)
at java.lang.ClassLoader.loadClass(ClassLoader.java:255)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:315)
What must I understand and what can I do to make it work?
I work on Solaris
Thank u

Answer 1

For starters, your program apparently doesn't call "loadLibrary" to load the shared library implementing your native method.