Java - copiar, borrar

package copia;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.Box;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JCheckBox;

import javax.swing.JButton;

import javax.swing.JTextArea;

import javax.swing.JScrollPane;

public class copiar extends JFrame{

 private JTextArea t1,t2;

 private JButton a, b;

 String T;

    public copiar()

 {

    this.setVisible(true);

    this.setSize(500,500);

   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

   Box c = Box.createHorizontalBox();

   T="maria teresa";

   t1= new JTextArea(T);

   c.add(new JScrollPane(t1));

   a= new JButton("copiar>>");

   b= new JButton("borrar");

   c.add(a);

   c.add(b);

   a.addActionListener(new ActionListener()

           {

        @Override

        public void actionPerformed(ActionEvent ae) {

        t2.setText(t1.getSelectedText());

        }

           });

   b.addActionListener(new ActionListener()

           {

        @Override

        public void actionPerformed(ActionEvent ee) {

        b.setEnabled(false);

        t2.setText("");

        }

           });

    t2= new JTextArea();

    c.add(new JScrollPane(t2));

    add(c);

            }

       }