Bug 419771

Description Mark McLaren 2013-10-17 18:22:53 EDT

A typical Jface application can create dozens or hundereds of 'zombie' threads which are never destroyed.

Tested on: OS X 10.8.4, Jface/SWT version 4.3.1, Oracle JDK 7 Update 45.

To reproduce: 
1. Run the snippet below using a debugger 
2. Click the 'Open Dialog' button. In the debugger, notice that a new Daemon Thread called Thread-1 has been created.
3. Close the dialog and click 'Open Dialog' again.  A new Daemon Thread called Thread-2 is created.
4. Open another OS X application (eg. Calculator) so that the Jface dialog is no longer the active window.
5. Click on the Jface dialog to make it active again - a new Daemon Thread called Thread-3 is created.

Note that this problem only appears when running the Oracle JVM.  The Apple JVM doesn't create these extra threads.


Snippet:
--------------------------
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class TestShellOpen {

	public static void main(String[] args) {


		Display display = new Display();
		final Shell shell = new Shell(display);
		Button btn = new Button(shell, SWT.PUSH);
		btn.setText("Open Dialog");
		btn.setBounds(25, 20, 150, 30);
		btn.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				 Dialog dialog = new Dialog(shell){};
				 dialog.open();
			}
		});
		
		shell.setSize(200, 200);
		shell.open();
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch())
				display.sleep();
		}
		display.dispose();
	}
}