done = true;
stopChecking();
	public LinkChecker() {		super("LinkChecker");        addWindowListener(new WindowAdapter() {			public void windowClosing(WindowEvent e) {			setVisible(false);			dispose();			System.exit(0);			}		});		setLayout(new BorderLayout());		p = new Panel();		p.setLayout(new FlowLayout());		p.add(new Label("URL"));		p.add(textFldURL = new TextField(40));		p.add(checkButton = new Button("Check URL"));		checkButton.addActionListener(new ActionListener() {			public void actionPerformed(ActionEvent e) {				doCheck();			}		});		p.add(killButton = new Button("Stop"));		killButton.addActionListener(new ActionListener() {			public void actionPerformed(ActionEvent e) {				if (t == null || !t.isAlive())					return;				done = true;			}		});		// Now lay out the main GUI - URL & buttons on top, text larger		add("North", p);		textWindow = new TextArea(80, 40);		add("Center", textWindow);	}