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?
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