Eclipse SWT notifyListeners

//-- Main.java --
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.List;
import org.eclipse.swt.widgets.Shell;

public class Main extends Composite {

  private List list = null;
  private Button button = null;

  public static void main(String[] args) {

    Display display = Display.getDefault();
    Shell shell = new Shell(display);
    shell.setLayout(new FillLayout());
    shell.setSize(new Point(300, 100));
    new Main(shell, SWT.NONE);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    display.dispose();
  }

  public Main(Composite parent, int style) {
    super(parent, style);
    initialize();
    listNotifyListeener();
  }

  private void initialize() {
    FillLayout fillLayout = new FillLayout();
    fillLayout.type = org.eclipse.swt.SWT.VERTICAL;
    list = new List(this, SWT.NONE);
    list.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {             
        List source = (List)e.getSource();
        boolean enabled = source.getSelectionCount() == 1;
        button.setEnabled(enabled);
        if (enabled) {          
          button.setText("Click " + source.getSelection()[0]);
        } else {
          button.setText("Select the item");
        }
      }
    });
    list.add("a");
    list.add("b");
    button = new Button(this, SWT.NONE);
    button.addSelectionListener(new org.eclipse.swt.events.SelectionAdapter() {
      public void widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
        list.deselectAll();
        listNotifyListeener();
        
      }
    });
    this.setLayout(fillLayout);
    setSize(new Point(300, 100));
  }

  private void listNotifyListeener() {
    Event e = new Event();
    list.notifyListeners(SWT.Selection, e);
  }

}