Actually, now i have another problem:

Here's my Java Code:
//ExceptionExperiment.java
public class ExceptionExperiment    {

    public native void testException() throws MyException;

    static    {
        System.loadLibrary("ExceptionExperimentImpl");
    }

    public ExceptionExperiment()    {
    }

    public static void main(String[] args)    {
        ExceptionExperiment app = new ExceptionExperiment();
        try    {
            app.testException();
            System.out.print("a");
        }catch(MyException e)    {
            e.printStackTrace();
        }
    }

    public class MyException extends Exception    {
        public MyException() {
            super();
           }

        public MyException(String s) {
            super(s);
           }
    }
}

And here's the C++ code:
//ExceptionExperimentImpl.cpp
JNIEXPORT void JNICALL Java_ExceptionExperiment_testException
 (JNIEnv *env, jobject obj)
{
                jclass cls =
env->FindClass("ExceptionExperiment$MyException");
                if (cls != NULL) {
                                env->ThrowNew(cls, NULL);
                }
                env->DeleteLocalRef(cls);
}

Now, this doesn't throw the MyException, but throws this:
//output
java.lang.NoSuchMethodError: ExceptionExperiment$MyException: method
<init>()V not found
    at ExceptionExperiment.testException(Native Method)
    at ExceptionExperiment.main(ExceptionExperiment.java:15)

the <init>()V method (which is the constructor, right?).
Am i doing something wrong here?