how to clear text fields in java jtextfield

JButton b = new JButton("Clear");
b.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent e){
        textfield.setText("");
        //textfield.setText(null); //or use this
    }
});

or

b.addSelectionListener(new SelectionAdapter()
  {
    @Override
    public void widgetSelected(SelectionEvent e)
    {
      textBox1.setText("");
      textBox2.setText("");
     }
  });