Java - Leer texto de archivo rtf que esta en un JtextPane

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class CodeTabs extends JTabbedPane {

  private JTextPane codearea;

  private JScrollPane scroll;

  public CodeTabs() {

    setTabPlacement(JTabbedPane.BOTTOM);

    codearea = new JTextPane();

    scroll = new JScrollPane(codearea, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);

    scroll.setPreferredSize(new Dimension(  300,300 ));

    JPanel panel = new JPanel( new BorderLayout() );

    panel.add( scroll, BorderLayout.CENTER );

    JButton comp = new JButton( "Print text" );

    comp.addActionListener( new ActionListener() {

      @Override

      public void actionPerformed( ActionEvent e ) {

        getCode();

      }

    } );

    panel.add( comp, BorderLayout.SOUTH );

    addTab( "Code", panel );

  }

  public String getCode() {

  //  String s = codearea.getText();

String s = codearea.getDocument().getText(0, codearea.getDocument().getLength());

    System.out.println(s);

    return s;

  }

  public static void main( String[] args ) {

    EventQueue.invokeLater( new Runnable() {

      @Override

      public void run() {

        JFrame frame = new JFrame( "TestFrame" );

        frame.getContentPane().add( new CodeTabs() );

        frame.setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );

        frame.pack();

        frame.setVisible( true );

      }

    } );

  }