The example below uses JNI interface to call a native function with
in turn calls fork() and then destroys the parent process.
This causes 1.1.6 java hang after the first native call but works
for (SunSoft) java 1.1.5 and 1.1.4.

$ cat testfork.c
#include "jni.h"
#include <stdio.h>
#include <string.h>

jstring JNICALL JNIEXPORT Java_TheButton_EstablishConnection(
     JNIEnv *env, jclass cl)
{
    char * p;
    int pid;
    printf("About to call fork\n");
    pid = fork();
    if (pid == -1) /* failure */
       printf("execution failed: unable to fork");
    else if (pid != 0) //parent
    {
       printf("the parent process is killed\n");
       exit(1);
    } else //child
    printf("Child process stays ");
    return((*env)->NewStringUTF(env, " "));
}

$ cat makefile
JDK1.1.6_HOME = /mde/apps/ilya/java/jdk1.1.6
libnative.so: testfork.c
        cc -xCC -I${JDK1.1.6_HOME}/include -I${JDK1.1.6_HOME}/include/solaris -I. -c testfork.c; cc -o libnative.so -G -KPIC -hlibnative.so testfork.o;

$ cat TestFork.java
import java.awt.*;
import java.awt.event.*;

public class TestFork {
    private Frame f;
    private Panel p2;

    public static void main(String args[]) {
        TestFork gui = new TestFork();
        gui.start();
    }

    public void start() {
        f = new Frame("Level 1 Lab");
        p2 = new Panel();
        p2.add(new TheButton("Test"));
        p2.add(new TheButton("Exit"));

        f.add(p2, "Center");
        f.setSize(200,100);
        f.setBackground(Color.white);
        f.setVisible(true);

    }
}

class TheButton extends Button {
  public static native String EstablishConnection();
   static
   {
     System.loadLibrary("native");
   }

    TheButton (String s) {
        super (s);
    }
    public boolean action (Event e, Object o) {
        if ("Test".equals(o)) {
            String errString;
            System.out.println("About to make native call");
            errString = EstablishConnection();
            System.out.println("Returned from native call");
            return true;
        } else if ("Exit".equals(o)) {
            System.exit(0);
        } else {
            return false;
        }
        return true;
    }
}



This works with

$ java -version
java version "1.1.4"
$ java -version
java version "1.1.5"

and causes hangs with

$ ../../jdk1.1.6/bin/java -version
java version "1.1.6"