Button b = new Button(container, SWT.PUSH);
        b.setText("test");
        b.addListener(SWT.Selection, new Listener()
        {
            private static final long serialVersionUID = 1L;
            
            @Override
            public void handleEvent(Event event)
            {
                System.out.println("pressed");
                try {
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("finished");
            }
        });