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  1. JDK
  2. JDK-4326731

Another java.awt.dnd.DropTarget causing JNI Global Reference leak?

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2
    • Resolution: Duplicate
    • Affects Version/s: 1.2.2_005
    • Fix Version/s: None
    • Component/s: client-libs
    • Labels:
    • Subcomponent:
    • CPU:
      sparc
    • OS:
      solaris_7

      Description


      Our customer (Ericsson Hewlett-Packard Telecommunications) claims that Bug ID 4294016 also exists in the Solaris version of JDK1.2.2_05 even if Bug ID 4294016 only is filed against the Windows_NT_95 version.

      He is still seeing a JNI Global Reference to his
      unreferenced objects when using JDK1.2.2_03 that has the fix for bug
      4224888.

      See the code example below.


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

      public class bugDropTargetLeak extends JFrame
      {
        DropTarget _dt;

        public bugDropTargetLeak()
        {
          super("Test Window");

          _dt = new DropTarget(this, null);

          setSize(400, 400);
        }

        protected void processWindowEvent(WindowEvent we)
        {
          if (we.getID() == WindowEvent.WINDOW_CLOSING)
          {
            System.out.println("window closing...");
            if (_dt != null)
            {
              _dt.setComponent(null);

              // The following is to workaround the bug in removeDropTarget(), i.e.
              // we need to call it twice for it to invoke the native
              // removeNativeDropTarget(). getPeer() is a deprecated method, but
              // it's the only workaround I know of.
              ((DropTargetPeer)getPeer()).removeDropTarget(_dt);

              // Clear out the variable just so we have less clutter when analyzing
              // using HAT.
              _dt = null;
            }
            dispose();
          }

          super.processWindowEvent(we);
        }

        public static void main(String[] args)
        {
          JFrame f = new JFrame("Main Window");
          Container cp = f.getContentPane();
          JButton b = new JButton("Click me to launch a leaked window");

          f.getContentPane().add(b, "North");
          b.addActionListener(new ActionListener()
       {
            public void actionPerformed(ActionEvent ae)
            {
              (new bugDropTargetLeak()).setVisible(true);
            }
          });

          b = new JButton("gc()");
          f.getContentPane().add(b, "South");
          b.addActionListener(new ActionListener()
          {
            public void actionPerformed(ActionEvent ae)
            {
              System.out.print("Calling system.gc() and System.runFinalization(): ");
              System.gc();
              System.out.print(".");
              System.gc();
              System.out.print(".");
              System.runFinalization();
              System.out.print(".");
              System.gc();
              System.out.print(".");
              System.gc();
              System.out.print(".");
              System.runFinalization();
              System.out.print(".");
              System.gc();
              System.out.print(".");
              System.gc();
              System.out.println(" done");
            }
          });

          f.addWindowListener(new WindowAdapter()
          {
            public void windowClosing(WindowEvent we)
            {
              System.exit(0);
            }
          });

          f.pack();
          f.setVisible(true);
        }
      }

      jonas.edberg@sweden 2000-03-31

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              • Assignee:
                rbrinkle Roger Brinkley (Inactive)
                Reporter:
                duke J. Duke (Inactive)
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                  Updated:
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