2 Replies Latest reply on Jul 10, 2014 9:31 PM by jschellSomeoneStoleMyAlias

    Any way to get fully qualified class name of Java class from C/C++?

    fbsd30

      Hello all,

       

      I am trying out some test JNI code before starting a project that will use a lot of Java API from C++.  I have seen old questions on the same topic and the general responses have always been you can call the getName method on a jclass instance.  However, with my test code always fails to find the getName method (I have other code that works with accessing static methods, inherited methods, non-virtual invocation of super-class methods etc).  Here is my code where I have tried various ways to get at the class name

       

              void classMethod()
              {
                if ( ! child ) return;
      
                jmethodID mid = env->GetMethodID( child, "getClass", "()Ljava/lang/Class;" );
      
                if ( mid )
                {
                  jclass clsObj = static_cast<jclass>( env->CallObjectMethod( obj, mid ) );
                  if ( ! clsObj ) std::cerr << "classMethod - Cannot retrieve Class object" << std::endl;
      
                  mid = env->GetMethodID( clsObj, "getName", "()Ljava/lang/String;" );
                  if ( mid )
                  {
                    jstring str = static_cast<jstring>( env->CallObjectMethod( clsObj, mid ) );
                    displayString( "classMethod", str );
                  }
                  else
                  {
                    std::cout << "classMethod - Cannot find getClass.getName, trying direct getName" << std::endl;
      
                    mid = env->GetMethodID( child, "getName", "()Ljava/lang/String;" );
      
                    if ( mid )
                    {
                      jstring str = static_cast<jstring>( env->CallObjectMethod( clsObj, mid ) );
                      displayString( "classMethod", str );
                    }
                    else std::cerr << "classMethod - Cannot find getClass.getName or getName directly on jclass" << std::endl;
                  }
                }
                else std::cerr << "classMethod - Cannot find getClass" << std::endl;
              }
      

       

      Note that if I just find "java/lang/Class" and then look up getName on it, it works fine.

       

      Environment:

      Mac OS X Mavericks

      java version "1.7.0_51"

      Java(TM) SE Runtime Environment (build 1.7.0_51-b13)

      Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)

       

      Thanks

      Rakesh