Java by API/org.eclipse.swt.events/DisposeListener

implements DisposeListener

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
public class MainClass {
  public static void main(String[] a) {
    Display display = new Display();
    // Create the main window
    Shell mainShell = new Shell(display);
    final Shell childShell = new Shell(mainShell);
    childShell.addDisposeListener(new DisposeListener() {
      public void widgetDisposed(DisposeEvent event) {
        System.out.println("Gotcha");
      }
    });
    childShell.setLayout(new FillLayout());
    childShell.setText("little brother");
    Button button = new Button(childShell, SWT.PUSH);
    button.setText("Close Me!");
    button.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent event) {
        childShell.close();
      }
    });
    childShell.open();
    while (!mainShell.isDisposed()) {
      if (!display.readAndDispatch()) {
        display.sleep();
      }
    }
    display.dispose();
  }
}