String Check GUI

package week9;

import javax.swing.*;  //for JFrame, JTextField, JTextArea
import java.awt.*;    //for Container, BorderLayout
import java.awt.event.*; //for WindowAdapter, ActionListener, ActionEvent

public class TextGUI extends JFrame {

    private static final int WIDTH = 800;
    private static final int HEIGHT = 500;

    private JLabel infoLabel;
    private JTextField textField;
    private JTextArea textArea;
    private final static String newline = "\n";


    private class EnterAction implements ActionListener
    {
            public void actionPerformed(ActionEvent e)
            {
                //StringCompare c = new StringCompare();

                String text = textField.getText();

                if(StringCompare.Compare(text) == true)
                    textArea.append(text + newline + "There are repeated characters." + newline);
                else
                    textArea.append(text + newline + "There are no repeated characters." + newline);

                textField.selectAll();
                textArea.setCaretPosition(textArea.getDocument().getLength());
            }
    }

    private class WindowDestroyer extends WindowAdapter
    {
        public void windowClosing(WindowEvent e)
        {
            dispose();
            System.exit(0);
        }
    }

    public TextGUI(String windowTitle)
    {
        super(windowTitle);
    setSize(WIDTH, HEIGHT);

        Container c1 = getContentPane();
        c1.setLayout( new BorderLayout());

    textField = new JTextField();
    c1.add(textField, BorderLayout.NORTH);

        textArea = new JTextArea();
    c1.add( textArea, BorderLayout.CENTER);
        textArea.setEditable(false);


    EnterAction myAction = new EnterAction();
    textField.addActionListener(myAction);

    WindowDestroyer myListener = new WindowDestroyer();
    addWindowListener(myListener);

    }

    public static void main(String[] args)
    {
    TextGUI app = new TextGUI("Zzzz");

    app.setVisible(true);

        System.out.println("Finished SimplApp.main()");
    }
}