Introduction

// Create a text field with some initial text
JTextField textfield = new JTextField("Initial Text");

// Create a text field with some initial text and a default number of columns.
// The number of columns controls the preferred width of the component;
// each column is rougly the size of an M in the current font.
int cols = 30;
textfield = new JTextField("Initial Text", cols);

// Listen for action events, which are fired when the user hits RETURN
textfield.addActionListener(new MyActionListener());

class MyActionListener implements ActionListener {
    public void actionPerformed(ActionEvent evt) {
        JTextField textfield = (JTextField)evt.getSource();
        process(textfield.getText());
    }
}