KeyEvent.VK_0 has the following syntax.
public static final int VK_0
In the following code shows how to use KeyEvent.VK_0 field.
/*from w ww .j av a2 s .c om*/ import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import javax.swing.JFrame; import javax.swing.JPanel; public class Main extends JPanel implements KeyListener { public Main() { addKeyListener(this); } public void keyPressed(KeyEvent evt) { int keyCode = evt.getKeyCode(); if (keyCode == KeyEvent.VK_0){ System.out.println("KeyEvent.VK_0"); } } public void keyReleased(KeyEvent evt) { } public void keyTyped(KeyEvent evt) { } public boolean isFocusTraversable() { return true; } public static void main(String[] args) { JFrame frame = new JFrame(); frame.setSize(300, 200); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.add(new Main()); frame.setVisible(true); } }