package kutility;
 
public interface ConsoleListener {
  void logMessage(String message);
}
 
----------------------------------------------------
 
package kutility;
 
import java.io.FilterOutputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.ArrayList;
 
public class Console
    extends FilterOutputStream {
  private static ArrayList registeredListeners = new ArrayList();
 
  static {
    // On its first use. Install the Console Listener
    PrintStream printStream =
        new PrintStream(
            new Console(new ByteArrayOutputStream())
        );
    System.setOut(printStream);
  }
 
  public Console(OutputStream out) {
    super(out);
  }
 
  /* Override Ancestor method */
  public void write(byte b[]) throws IOException {
    String str = new String(b);
    logMessage(str);
  }
 
  /* Override Ancestor method */
  public void write(byte b[], int off, int len) throws IOException {
    String str = new String(b, off, len);
    logMessage(str);
  }
 
  /* Override Ancestor method */
  public void write(int b) throws IOException {
    String str = new String(new char[] { (char) b});
    logMessage(str);
  }
 
  public static void registerOutputListener(ConsoleListener listener) {
    // we don't register null listeners
    if (listener != null) {
      registeredListeners.add(listener);
    }
  }
 
  public static void removeOutputListener(ConsoleListener listener) {
    if (listener != null) {
      registeredListeners.remove(listener);
    }
  }
 
  private static void logMessage(String message) {
    // Log output to each listener
    int count = registeredListeners.size();
    for (int i = 0; i < count; i++) {
      ( (ConsoleListener) registeredListeners.get(i)).logMessage(message);
    }
  }
}
 
----------------------------------------------------
 
package kutility;
 
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
public class ConsoleTest
    extends JFrame implements ConsoleListener {
  private JScrollPane jScrollPane1 = new JScrollPane();
  private JTextArea jTextArea1 = new JTextArea();
  private JButton msgButton = new JButton("Log Message");
 
  public ConsoleTest() {
    try {
      jbInit();
    }
    catch (Exception ex) {
      ex.printStackTrace();
    }
  }
 
  private void jbInit() throws Exception {
    this.getContentPane().setLayout(new FlowLayout());
    this.getContentPane().add(jScrollPane1);
    jTextArea1.setRows(10);
    jTextArea1.setColumns(20);
    jTextArea1.setText("");
    this.getContentPane().add(jScrollPane1);
    jScrollPane1.getViewport().add(jTextArea1);
    this.getContentPane().add(this.msgButton);
 
    this.msgButton.addActionListener(
        new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        System.out.println("Current Date and Tiem is:");
        System.out.println(new java.util.Date());
      }
    }
    );
 
    // Registe this frame as Console Listener
    Console.registerOutputListener(this);
  }
 
  public static void main(String[] args) {
    ConsoleTest consoletest = new ConsoleTest();
    consoletest.setBounds(10, 10, 300, 300);
    consoletest.setVisible(true);
 
  }
 
// Implement the ConsoleListener interface method to log message to Text Area
  public void logMessage(String message) {
    this.jTextArea1.append(message);
  }
 
  public void msgButton_actionPerformed(ActionEvent e) {
    // Log cuttent date and time
    System.out.println(new java.util.Date());
  }
 
}