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

public class redirectedframe extends frame {
    textarea atextarea = new textarea();
    printstream aprintstream  =
       new printstream(
         new filteredstream(
           new bytearrayoutputstream()));

    boolean logfile;

    redirectedframe(boolean logfile) {
       this.logfile = logfile;
       system.setout(aprintstream);
       system.seterr(aprintstream);
       settitle("error message");
       setsize(500,300);
       setlayout(new borderlayout());
       add("center" , atextarea);
       displaylog();
       addwindowlistener
          (new windowadapter() {
             public void windowclosing(windowevent e) {
                dispose();
                }
             }
          );
       }

    class filteredstream extends filteroutputstream {
       public filteredstream(outputstream astream) {
          super(astream);
          }

       public void write(byte b[]) throws ioexception {
          string astring = new string(b);
          atextarea.append(astring);
          }

       public void write(byte b[], int off, int len) throws ioexception {
          string astring = new string(b , off , len);
          atextarea.append(astring);
          if (logfile) {
             filewriter awriter = new filewriter("error.log", true);
             awriter.write(astring);
             awriter.close();
             }
          }
       }

    public void displaylog() {
       dimension dim = gettoolkit().getscreensize();
       rectangle abounds = getbounds();
       dimension dd = getsize();
       setlocation((dim.width - abounds.width) / 2,
          (dim.height - abounds.height) / 2);
       setvisible(true);
       requestfocus();
       }

    public static void main(string s[]){
       try {
          // force an exception for demonstration purpose
          class.forname("unknown").newinstance();
          }
       catch (exception e) {
          // for applet, always redirectedframe(false)
          redirectedframe r = new redirectedframe(true);
          e.printstacktrace();
          }
       }
    }