Java tutorial
import java.awt.GridLayout; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextField; import javax.swing.event.DocumentEvent; import javax.swing.event.DocumentListener; public class Main { public static void main(String[] args) { JPanel mainPanel = new JPanel(); JTextField field = new JTextField(20); JTextField field1 = new JTextField(20); field.getDocument().addDocumentListener(new DocumentListener() { @Override public void changedUpdate(DocumentEvent e) { updateLabel(e); } @Override public void insertUpdate(DocumentEvent e) { updateLabel(e); } @Override public void removeUpdate(DocumentEvent e) { updateLabel(e); } private void updateLabel(DocumentEvent e) { field1.setText(field.getText()); } }); mainPanel.setLayout(new GridLayout(1, 0, 10, 0)); mainPanel.add(field); mainPanel.add(field1); JFrame frame = new JFrame(); frame.getContentPane().add(mainPanel); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.pack(); frame.setVisible(true); } }