Name: yyT116575 Date: 08/07/2001


java version "1.3.1"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1-b24)
Java HotSpot(TM) Client VM (build 1.3.1-b24, mixed mode)

The following code leaks one instance of ZMemoryLeakWindow, but only when
opening the popup of the combobox. In our case, this means that everytime a
combobox is opened, the whole frame will not be garbage-collected, meaning that
virtually everything remains in memory.

just run test.gerd.ZMemoryLeak and press the Show-Frame button. This will open
a ZMemoryLeakWindow(LEAK-Window) which will allocate a lot of memory. If you
then press close in the LEAK-Window, everything gets garbage-collected. But if
you klick on the combobox before closing (opening the popup) the LEAK-Window
will not get garbage-collected.

(PS: I looked for similar bugs in the bug database, but found only bugs related
to popup-menus).

here's the code

********************************************************

package test.gerd;

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class ZMemoryLeak extends JFrame {

  public static void main(String[] args) {
    new ZMemoryLeak().setVisible(true);
  }

  public ZMemoryLeak() {
    super("MAIN");
    getContentPane().setLayout(new BorderLayout());
    getContentPane().add(createBtn(), BorderLayout.SOUTH);
    setSize(800, 600);
    setDefaultCloseOperation(3);
  }

  private void closeFrame() {
    setVisible(false);
    dispose();
  }

  private JComponent createBtn() {
    JPanel p = new JPanel(new GridLayout());

    JButton btn = new JButton("Show Frame");
    btn.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent ev) {
        new ZMemoryLeakWindow().setVisible(true);
      }
    });
    p.add(btn);

    return p;
  }
}

***********************************************************

package test.gerd;

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class ZMemoryLeakWindow extends JFrame {

  public static void main(String[] args) {
    new ZMemoryLeak().setVisible(true);
  }

  private char[] buff= new char[1024*1024*12];

  public ZMemoryLeakWindow() {
    super("LEAK-Window");
    getContentPane().setLayout(new BorderLayout());
    getContentPane().add(new JComboBox(), BorderLayout.NORTH);
    getContentPane().add(createBtn(), BorderLayout.SOUTH);
    setSize(800, 600);
    setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
  }

  private void closeFrame() {
    setVisible(false);
    dispose();
  }

  private JComponent createBtn() {
    JPanel p = new JPanel(new GridLayout());

    JButton btn = new JButton("Close");
    btn.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent ev) {
        closeFrame();
      }
    });

    p.add(btn);

    return p;
  }
}
(Review ID: 129476)
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