Name: paC48320 Date: 11/13/97


Platform: Sun Ultra 1 running Solaris 2.5
Java JDK used: JDK1.1.5D

1. Execute the java program, "MenuBarBug"
2. Source code, as follows:
/*
 * MenuBarBug.java
 * Test program to reproduce MenuBarBug.
 * Bug Description
 * Setting a menubar as a Frame MenuBar and removing it before the
 * frame is realized and then setting it again after the Frame is
 * realized causes a null-pointer exception.
 * Running the test
 * - Compile and run MenuBarBug.java
 * - You will see a Frame with an empty menubar and a pushbutton
 * - Press the pushbutton
 * - You will see a null-pointer exception at this point
 * @author Sridhar Reddy (###@###.###)
 */
import java.awt.Frame;
import java.awt.MenuBar;
import java.awt.Button;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class MenuBarBug extends Frame implements ActionListener
{
  // constructor
  public MenuBarBug()
  {
    super("MenuBarBug");
    // create menubars
    menubar1 = new MenuBar();
    menubar2 = new MenuBar();
    // set menubar1 as the Frame's MenuBar and replace it with
    // menubar2
    setMenuBar(menubar1);
    setMenuBar(menubar2);
    // create a button to change menubar back to menubar1
    button = new Button("Change MenuBar");
    add(button);
    button.addActionListener(this);
    setSize(200, 200);
  }
  // ActionListener implementation
  public void actionPerformed(ActionEvent e)
  {
    // set the menubar back to MenuBar
    setMenuBar(menubar1);
  }
  // instance variables
  MenuBar menubar1;
  MenuBar menubar2;
  Button button;
  // test main
  public static void main(String[] args)
  {
    MenuBarBug window = new MenuBarBug();
    window.setVisible(true);
  }
}

3. Program dumps core. Message follows:
SIGSEGV 11* segmentation violation
    si_signo [11]: SIGSEGV 11* segmentation violation
    si_errno [0]: Error 0
    si_code [1]: SEGV_MAPERR [addr: 0x0]

        stackbase=EFFFE900, stackpointer=EFFFE640

Full thread dump:
    "AWT-Motif" (TID:0xee704f48, sys_thread_t:0xedfb1db8, state:R) prio=5
    "AWT-Input" (TID:0xee704f68, sys_thread_t:0xedfe1db8, state:R) prio=5
    "AWT-EventQueue-0" (TID:0xee704f80, sys_thread_t:0xee011db8, state:R) prio=5
    "Finalizer thread" (TID:0xee703c48, sys_thread_t:0xee2c1db8, state:R) prio=1
    "Async Garbage Collector" (TID:0xee703c90, sys_thread_t:0xee2f1db8, state:R) prio=1
    "Idle thread" (TID:0xee703a08, sys_thread_t:0xee3c1db8, state:R) prio=0
    "Clock" (TID:0xee700088, sys_thread_t:0xee3f1db8, state:CW) prio=12
    "main" (TID:0xee7000b0, sys_thread_t:0x685f8, state:R) prio=5 *current thread*
        sun.awt.motif.MFramePeer.setMenuBar(MFramePeer.java:112)
        java.awt.Frame.addNotify(Frame.java:205)
        java.awt.Window.show(Window.java:144)
        java.awt.Component.show(Component.java:498)
        java.awt.Component.setVisible(Component.java:460)
        MenuBarBug.main(MenuBarBug.java:43)
Monitor Cache Dump:
    sun.awt.motif.MToolkit@EE704D48/EE75F138: owner "main" (0x685f8, 1 entry)
Registered Monitor Dump:
    Thread queue lock: <unowned>
    Name and type hash table lock: <unowned>
    String intern lock: <unowned>
    JNI pinning lock: <unowned>
    JNI global reference lock: <unowned>
    BinClass lock: <unowned>
    Class loading lock: <unowned>
    Java stack lock: <unowned>
    Code rewrite lock: <unowned>
    Heap lock: <unowned>
    Has finalization queue lock: <unowned>
    Finalize me queue lock: <unowned>
    Monitor IO lock: <unowned>
    Child death monitor: <unowned>
    Event monitor: <unowned>
    I/O monitor: <unowned>
    Alarm monitor: <unowned>
        Waiting to be notified:
            "Clock"
    Sbrk lock: <unowned>
    Monitor cache expansion lock: <unowned>
    Monitor registry: owner "main" (0x685f8, 1 entry)
Thread Alarm Q:
Abort (core dumped)

4. See above
5. N/A.
(Review ID: 19597)
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