TextField can catch keyinput event if it's made via Input Method.

The following code is to reject an input of "z", if z is inputed from IME/IM
it won;t be consumed.


import java.awt.*;
import java.awt.event.*;

public class EchoChar {
  public static void main(String args[]) {
    new EchoChar().run();
  }

  Frame fp;
  TextField tf;

  void run() {
    fp = new Frame("Test");
    fp.add(tf = new TextField(50));
    tf.addKeyListener(
      new KeyAdapter() {
        public void keyPressed(KeyEvent e) {
          if(e.getKeyChar() == 'Z')
            e.consume();
        }
      }
    );
    fp.pack();
    fp.show();
  }
}