On some platforms, hitting the “Enter” key to terminate input to a TextField will cause the whole dialog box to disappear, as if you had clicked an “OK” button. If you are adamant about conforming to platform conventions this may be fine. But if your customers are accountants using the numeric pad to enter data, they may be less than satisfied. It is easy enough to extend the TextField class so that an “Enter” will behave the same as a “Tab”, transferring the focus to the next input Component:

 import java.awt.*;import java.awt.event.*;public class PatientField extends TextField                       implements ActionListener {// Constructor    public PatientField(int width) {        super(width);        addActionListener(this);    }// Action handler    public void actionPerformed(ActionEvent ev) {        transferFocus();    }}