JNI: Class not found or FindClass returns NULL

[Ibrahim]

Hi; I'm trying JNI with C++. But I get this error: Class not found!.
Code.java:

package com.xxx;

public class Code
{
  public void getMessage()
  {
    System.out.println("Hello World!");
  }
}

main.cpp:

#include <jni.h>
#include <iostream>
using namespace std;

int main(int argc, char* argv[])
{
  JavaVM* jvm;
  JNIEnv* env;
  JavaVMInitArgs jvm_args;
  JavaVMOption options[1];

  options[0].optionString = "-Djava.class.path=myclasses";
  jvm_args.version = JNI_VERSION_1_2;
  jvm_args.options = options;
  jvm_args.nOptions = 1;
  jvm_args.ignoreUnrecognized = JNI_TRUE;

  jint res = JNI_CreateJavaVM(&jvm, (void**)&env, &jvm_args);
  if (res < 0)
  {
    cout << "Cannot create JVM!\n";
    exit(1);
  }

  jclass class_ = env->FindClass("com/xxx/Code");
  if (class_ == 0)
  {
    cout << "Code class not found!\n";
    exit(1);
  }

  jmethodID method_id = env->GetMethodID(class_, "getMessage", "()V");
  if (method_id == 0)
  {
    cout << "getMessage() method not found!\n";
    exit(1);
  }

  env->CallVoidMethod(class_, method_id);

  return 0;
}

Directory for my files:

I tried -Djava.class.path=myclasses/com/xxx and env->FindClass("Code");. Also I tried -Djava.class.path=myclasses and env->FindClass("com/xxx/Code");. But both not working. What is reason of Code class not found! message?

[p3c0]

@Ibrahim Have you checked whether that Java code works at first without calling from C++?

[raven-worx]

@Ibrahim
There are some open question (at least from my side):

1. where do you have this example code from?
2. how do you execute this code in your android environment?
3. how does your Activity and manifest file look like?

[Ibrahim]

@p3c0 yes, Java class is works!
@raven-worx
1- I wrote the Java class.
2 and 3- This application is console app, not Android app.

But I tried this Java code with QAndroidExtras, and I see **Hello World!" text on terminal. But when I used pure JNI (jni.h file), I saw Class not found!.

I don't know reason of this message. I researched it, but I did'n find the reason. Why there are not information this problem? I asked very much this question in the place, but I don't get a result.

[raven-worx]

@Ibrahim
have you read the invocation API chapter?

Please also try to specify an absolute class path.

[Ibrahim]

@raven-worx result is same. I didn't set CLASSPATH or LD_LIBRARY_PATH . Is this reason of problem?