Why do i get this message when i run the java program?

Question

Java Code :

package Package;

public class MyExceptionTester {

private native void compute() throws Exception;

public static void main(String... args) {
    try {
        MyExceptionTester met = new MyExceptionTester();
        met.compute(); // This method will throw an exception which gets printed from the catch block
    } catch(Exception exc) {
        System.out.println("From Java :" + exc);
    }
}

static {
    System.loadLibrary("MyExceptionTester");
 }
}

C++ Code :

#include "iostream"
#include "Package_MyExceptionTester.h"

void Java_Package_MyExceptionTester_compute
   (JNIEnv *env, jobject obj) {
        jthrowable exc;
        try {
            jint i = 1/0;
            throw "C++ Message : Hey ! Can't Divide By Zero";
        } catch(char *str) {
            jclass excClass = env->FindClass("java/lang/Exception");
            if(excClass == NULL) {
                    return;
                }
            env->ThrowNew(excClass,str);
          }

}

When i run the java program after including the dll i get the following message :

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  EXCEPTION_INT_DIVIDE_BY_ZERO (0xc0000094) at pc=0x65c4121a, pid=5292, tid=6000 
#
# JRE version: 7.0
# Java VM: Java HotSpot(TM) Client VM (20.0-b01 mixed mode, sharing windows-x86 )
# Problematic frame:
# C  [MyExceptionTester.dll+0x121a] 
#
# An error report file with more information is saved as:
# W:\elita\jnitesters\workspace\java\JNI\build\classes\hs_err_pid5292.log
#
# If you would like to submit a bug report, please visit:
#   http://java.sun.com/webapps/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#

Why do i get this message ? And why don't i see the output which should be a message printed from the java catch block .

Answer 1

 jint i = 1/0;
 throw "C++ Message : Hey ! Can't Divide By Zero";

This exception is not caught by your try/catch block, as the program crashes before the throw statement. And a division by 0 is not an exception you can catch.

Perhaps something that might help:

int d = 0;
jthrowable exc;
try 
{
    if ( d == 0 )
        throw "C++ Message : Hey ! Can't Divide By Zero";
    jint i = 1/d;
} catch(char *str) 
{
    jclass excClass = env->FindClass("java/lang/Exception");
    if(excClass == NULL) 
    {
       return;
    }
    env->ThrowNew(excClass,str);
}

Answer 2

Native code call has been inside JVM. Since the native program crashes before throwing exception, the crash in native programs causes JVM to crash too.