Invoking JNI function using gcj

Vaijayanthi Mala Suresh vaijayanthimalas@gmail.com
Wed May 27 08:34:00 GMT 2009


I have written an HelloWorld.java as given below

public class HelloWorld {
   public native void natPrint();

   public HelloWorld()
   {
     System.out.println("Hello from constructor");
   }
   public void printline()
   {
     System.out.println("Hello from printline");
 natPrint()
   }
   public static void main(String [] args) {
     System.out.println("Hello from main");
     HelloWorld ht = new HelloWorld();
     ht.printline();
   }
static
{
 System.loadLibrary("HelloWorld");
}
 }

I have compiled it with gcj as given below
gcj -c -fjni HelloWorld.java
gcj -C HelloWorld.java
gcjh HelloWorld
gcjh -jni HelloWorld -o HelloNative.h
gcjh -stubs -jni HelloWorld
g++ -I. -c HelloWorld.c natHelloWorld.o
gcj -shared natHelloWorld.o -o libHelloWorld.so

Copied the .so file into the folder as /lib and it set in LD_LIBRARY_PATH.

I have a cppstartup.cpp which does the JVM Initialization and has
invokes HelloWorld as given below

#include "HelloWorld.h"

using namespace java::lang;

      try
      {
JvCreateJavaVM(NULL);
JvAttachCurrentThread(NULL, NULL);

      String *message = JvNewStringLatin1("Hello from C++");
      JvInitClass(&System::class$);
      System::out->println(message);

  HelloWorld *ht = new HelloWorld();
      ht->printline();

      JvDetachCurrentThread();
      }
      catch (Throwable *t)
      {
        System::err->println(JvNewStringLatin1("Unhandled Java exception:"));
       t->printStackTrace();
      }

This throws an exception  me "Unsatisfied Linker Error"

Can someone help me in this regard?



More information about the Java mailing list