Callback methods

Question

I'm receiving the same error over and over, and tried pretty everything now. It seems that the method is not found, but it's there alright.
In fact, I've more or less copied the example from the jni-tutorial, chapter callbacks.
The error is thrown when GetMethodID is called.
Here's a code snippet
Java part:
==========
     //     inside native wrapper class
     public void testcallback(int testInt){
          System.err.println("testcallback "+testInt);
C++ part:
=========
     //     inside native c++ class
     //     already defined:
          jobject m_Obj;
          JNIEnv *m_pEnv;
     void firecallback()
          jclass cls=m_pEnv->GetObjectClass(m_Obj);
          jmethodID mid=m_pEnv->GetMethodID(cls,"testcallback","(I)V");
          if(mid==0)
               return;
          m_pEnv->CallVoidMethod(m_Obj,mid,2002);
     }This is the error I get:
java.lang.NoSuchMethodError: testcallback

Answer 1

I've forgotten to make global references out of those local ones, so deny that snippet.
But, using this pure local, doesn't work either:
JNIEXPORT jint JNICALL Java_xantus_xnative_ExcelWrapper_startcallback
  (JNIEnv *env, jclass obj)
     jclass cls=env->GetObjectClass(obj);
     jmethodID mid=env->GetMethodID(cls,"testcallback","(I)V");
     if(mid==0)
          return -1;
     env->CallVoidMethod(obj,mid,0);
     return 0;
} I'm still receiving this error:
java.lang.NoSuchMethodError: testcallback
This becomes rather annoying...