try
  {
    console = new Console();
  }
  catch(Exception e)
  {
  } 

public class Console extends javax.swing.JFrame {
        PipedInputStream piOut;
        PipedInputStream piErr;
        PipedOutputStream poOut;
        PipedOutputStream poErr;
        javax.swing.JTextArea textArea = new javax.swing.JTextArea();
    
        public Console() throws IOException {
            // Set up System.out
            piOut = new PipedInputStream();
            poOut = new PipedOutputStream(piOut);
            System.setOut(new PrintStream(poOut, true));
    
            // Set up System.err
            piErr = new PipedInputStream();
            poErr = new PipedOutputStream(piErr);
            System.setErr(new PrintStream(poErr, true));
    
            // Add a scrolling text area
            textArea.setEditable(false);
            textArea.setRows(20);
            textArea.setColumns(50);
            getContentPane().add(new javax.swing.JScrollPane(textArea), BorderLayout.CENTER);
            pack();
            setVisible(true);
    
            // Create reader threads
            new ReaderThread(piOut).start();
            new ReaderThread(piErr).start();
        }
    
        class ReaderThread extends Thread {
            PipedInputStream pi;
    
            ReaderThread(PipedInputStream pi) {
                this.pi = pi;
            }
    
            public void run() {
                final byte[] buf = new byte[1024];
                try {
                    while (true) {
                        final int len = pi.read(buf);
                        if (len == -1) {
                            break;
                        }
                        javax.swing.SwingUtilities.invokeLater(new Runnable() {
                            public void run() {
                                textArea.append(new String(buf, 0, len));
    
                                // Make sure the last line is always visible
                                textArea.setCaretPosition(textArea.getDocument().getLength());
    
                                // Keep the text area down to a certain character size
                                int idealSize = 1000;
                                int maxExcess = 500;
                                int excess = textArea.getDocument().getLength() - idealSize;
                                if (excess >= maxExcess) {
                                    textArea.replaceRange("", 0, excess);
                                }
                            }
                        });
                    }
                } catch (IOException e) {
                }
            }
        }
    }
 

  try
  {
    Console console = new Console();
  }
  catch(Exception e)
  {
  }  

Console console;

void setup()
{
  try
  {
    console = new Console();
  }
  catch(Exception e)
  {
  }
  println("Test");
} 

void draw()
{
}

public class Console extends javax.swing.JFrame {
  PipedInputStream piOut;
  PipedInputStream piErr;
  PipedOutputStream poOut;
  PipedOutputStream poErr;
  javax.swing.JTextArea textArea = new javax.swing.JTextArea();

  public Console() throws IOException {
    // Set up System.out
    piOut = new PipedInputStream();
    poOut = new PipedOutputStream(piOut);
    System.setOut(new PrintStream(poOut, true));

    // Set up System.err
    piErr = new PipedInputStream();
    poErr = new PipedOutputStream(piErr);
    System.setErr(new PrintStream(poErr, true));

    // Add a scrolling text area
    textArea.setEditable(false);
    textArea.setRows(20);
    textArea.setColumns(50);
    getContentPane().add(new javax.swing.JScrollPane(textArea), BorderLayout.CENTER);
    pack();
    setVisible(true);

    // Create reader threads
    new ReaderThread(piOut).start();
    new ReaderThread(piErr).start();
  }

  class ReaderThread extends Thread {
    PipedInputStream pi;

    ReaderThread(PipedInputStream pi) {
      this.pi = pi;
    }

    public void run() {
      final byte[] buf = new byte[1024];
      try {
        while (true) {
          final int len = pi.read(buf);
          if (len == -1) {
            break;
          }
          javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
              textArea.append(new String(buf, 0, len));

              // Make sure the last line is always visible
              textArea.setCaretPosition(textArea.getDocument().getLength());

              // Keep the text area down to a certain character size
              int idealSize = 1000;
              int maxExcess = 500;
              int excess = textArea.getDocument().getLength() - idealSize;
              if (excess >= maxExcess) {
                textArea.replaceRange("", 0, excess);
              }
            }
          }
          );
        }
      } 
      catch (IOException e) {
      }
    }
  }
}
 

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

Console console;

void setup()
{
  size(800, 600);

  try
  {
    console = new Console();
  }
  catch(Exception e)
  {
  }

  println("This is some text printed to the console");
}

void draw()
{
  println("test and so on");
  delay(100);
}

public class Console extends WindowAdapter implements WindowListener, ActionListener, Runnable
{
  private JFrame frame;
  private JTextArea textArea;
  private Thread reader;
  private Thread reader2;
  private boolean quit;

  private final PipedInputStream pin=new PipedInputStream(); 
  private final PipedInputStream pin2=new PipedInputStream(); 

  Thread errorThrower; // just for testing (Throws an Exception at this Console

  public Console()
  {
    // create all components and add them
    frame=new JFrame("Java Console");
    Dimension screenSize=Toolkit.getDefaultToolkit().getScreenSize();
    Dimension frameSize=new Dimension((int)(screenSize.width/2),(int)(screenSize.height/2));
    int x=(int)(frameSize.width/2);
    int y=(int)(frameSize.height/2);
    frame.setBounds(x,y,frameSize.width,frameSize.height);

    textArea=new JTextArea();
    textArea.setEditable(false);
    JButton button=new JButton("clear");

    frame.getContentPane().setLayout(new BorderLayout());
    frame.getContentPane().add(new JScrollPane(textArea),BorderLayout.CENTER);
    frame.getContentPane().add(button,BorderLayout.SOUTH);
    frame.setVisible(true);		

    frame.addWindowListener(this);		
    button.addActionListener(this);

    try
    {
      PipedOutputStream pout=new PipedOutputStream(this.pin);
      System.setOut(new PrintStream(pout,true)); 
    } 
    catch (java.io.IOException io)
    {
      textArea.append("Couldn't redirect STDOUT to this console\n"+io.getMessage());
    }
    catch (SecurityException se)
    {
      textArea.append("Couldn't redirect STDOUT to this console\n"+se.getMessage());
    } 

    try 
    {
      PipedOutputStream pout2=new PipedOutputStream(this.pin2);
      System.setErr(new PrintStream(pout2,true));
    } 
    catch (java.io.IOException io)
    {
      textArea.append("Couldn't redirect STDERR to this console\n"+io.getMessage());
    }
    catch (SecurityException se)
    {
      textArea.append("Couldn't redirect STDERR to this console\n"+se.getMessage());
    } 		

    quit=false; // signals the Threads that they should exit

    // Starting two seperate threads to read from the PipedInputStreams				
    //
    reader=new Thread(this);
    reader.setDaemon(true);	
    reader.start();	
    //
    reader2=new Thread(this);	
    reader2.setDaemon(true);	
    reader2.start();

    // testing part
    // you may omit this part for your application
    // 
    System.out.println("Hello World 2");
    System.out.println("All fonts available to Graphic2D:\n");
    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
    String[] fontNames=ge.getAvailableFontFamilyNames();
    for(int n=0;n<fontNames.length;n++)  System.out.println(fontNames[n]);		
    // Testing part: simple an error thrown anywhere in this JVM will be printed on the Console
    // We do it with a seperate Thread becasue we don't wan't to break a Thread used by the Console.
    System.out.println("\nLets throw an error on this console");	
    errorThrower=new Thread(this);
    errorThrower.setDaemon(true);
    errorThrower.start();					
  }

  public synchronized void windowClosed(WindowEvent evt)
  {
    quit=true;
    this.notifyAll(); // stop all threads
    try { 
      reader.join(1000);
      pin.close();   
    } 
    catch (Exception e){
    }		
    try { 
      reader2.join(1000);
      pin2.close(); 
    } 
    catch (Exception e){
    }
    System.exit(0);
  }		

  public synchronized void windowClosing(WindowEvent evt)
  {
    frame.setVisible(false); // default behaviour of JFrame	
    frame.dispose();
  }

  public synchronized void actionPerformed(ActionEvent evt)
  {
    textArea.setText("");
  }

  public synchronized void run()
  {
    try
    {			
      while (Thread.currentThread()==reader)
      {
        try { 
          this.wait(100);
        }
        catch(InterruptedException ie) {
        }
        if (pin.available()!=0)
        {
          String input=this.readLine(pin);
          textArea.append(input);
          textArea.setCaretPosition(textArea.getDocument().getLength());

        }
        if (quit) return;
      }

      while (Thread.currentThread()==reader2)
      {
        try { 
          this.wait(100);
        }
        catch(InterruptedException ie) {
        }
        if (pin2.available()!=0)
        {
          String input=this.readLine(pin2);
          textArea.append(input);
          textArea.setCaretPosition(textArea.getDocument().getLength());

        }
        if (quit) return;
      }			
    } 
    catch (Exception e)
    {
      textArea.append("\nConsole reports an Internal error.");
      textArea.append("The error is: "+e);			
    }
  }

  public synchronized String readLine(PipedInputStream in) throws IOException
  {
    String input="";
    do
    {
      int available=in.available();
      if (available==0) break;
      byte b[]=new byte[available];
      in.read(b);
      input=input+new String(b,0,b.length);														
    }
    while( !input.endsWith("\n") &&  !input.endsWith("\r\n") && !quit);
    return input;
  }				
}