Problem with JNI hello world

Question

I found some tutorial on SUN site on how to use JNI. I'm using Eclipse to compije Java and C (via Cygwin) files. Here are complete files:
Hello.java:
class Hello
     public native void sayHello();
     static
          try
          System.loadLibrary("hello");
          catch(Exception e)
               System.out.println("exc");
     public static void main(String[] args)
          Hello h = new Hello();
          h.sayHello ();
}Hello.c:
#include <mingw/_mingw.h> //because there are some types needed for JNI
#include <jni.h>
#include "Hello.h"
#include <stdio.h>
JNIEXPORT void JNICALL Java_Hello_sayHello
  (JNIEnv *env, jobject obj)
     printf("Hello world!\n");
     return;
}Makefile:
hello.dll : Hello.o Hello.def
     gcc -g -shared -Wl,--kill-at -o hello.dll Hello.o hello.def
Hello.o : Hello.c Hello.h
     gcc -c -g -I"$(JAVA_HOME)\include" -I"$(JAVA_HOME)\include\win32" Hello.c -o Hello.o
Hello.h : Hello.class
     javah -jni Hello
clean :
     rm Hello.h
     rm Hello.o
     rm hello.dllHello.def
EXPORTS
Java_Hello_sayHelloEverything goes well, but when I run java program it does nothin (it should print message, but it just exit without any error).I'm sure that it's something stupid, but I cant see what. Can anyone tell me what am I doing wrong?
Thenks.

Answer 1

Answer 1: yes, there was no problem. I compiled and started simple 'hello world' program from Cygwin and from WinXP console, and it worked well.
Answer 2: This is weird, I changed code to this:
Hello.java:
     public native int getInt();
          System.out.println("Returned int is " + h.getInt());Hello.c:
JNIEXPORT jint JNICALL Java_Hello_getInt
  (JNIEnv *env, jobject obj)
     return 25;
}It does not print anything. I started this program from Cygwin and from WinXP console, and from Eclipse. Only if I debug in Eclipse (step by step) I get:
Returned int is 25and still I don't get Hello string printed (even if I go step by step). It looks like cygwin has some problem with OS. Do you have any idea what to do, I'm a bit confused?
Thank you.
Message was edited by:
zly