Redirecting System.err to a JOptionPane

Question

Hello,
I tried to write a piece of code which shows all exceptions in a JOptionPane instead of the console. But I meet two difficulties:
1. I don't know how to detect the line count of the error message (so that currently I have to display the optionPane for each error line, which is unacceptable).
2. I receive more error messages than expected. The produced parse error gives 5 lines on a console, but here I receive 60.
What's wrong?
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
class Redirecting extends JFrame {
  public Redirecting() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(300,300);
    JTextAreaOutputStream err= new JTextAreaOutputStream();
    System.setErr(new PrintStream(err));
    JButton b= new JButton("Produce error");
    b.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent evt) {
     System.out.println(Integer.parseInt("1"));
     System.out.println(Integer.parseInt("2"));
     System.out.println(Integer.parseInt("Error"));
    add(b, BorderLayout.SOUTH);
    setVisible(true);
  public static void main(String[] args) throws Exception {
    EventQueue.invokeLater(new Runnable() {
      public void run() {
     new Redirecting();
  class JTextAreaOutputStream extends OutputStream {
    int icnt=0;
    private JTextArea area;
    public JTextAreaOutputStream() {
      area= new JTextArea();
    public void flush() throws IOException {
      JOptionPane.showMessageDialog(Redirecting.this, area, "Error",
                              JOptionPane.ERROR_MESSAGE);
//      area.setText("");
    public void write(byte b[]) throws IOException {
      area.append(new String(b));
    public void write(byte b[], int off, int len) throws IOException {
      System.out.println(icnt++);
      String s = new String(b , off , len);
      area.append(s);
      flush(); // to make error lines visible
    public void write(int b) throws IOException {
      area.append(String.valueOf(b));
}

Answer 1

maybe this ?
      * recieving error for testing
      * @param e
     protected void bt_generateError_actionPerformed(ActionEvent e) {
          DateFormat fo = new SimpleDateFormat("mm.dd.yyyy");
          try {
               // Here reciev parsing error
               fo.parse("sacascsa");
          } catch (ParseException e1) {
               String exception = Util.formateException(e1.getStackTrace());
               // show error
               Util.showException(frame, exception);
      * utilita
      * @author Dima
     public static class Util {
           * formateException formating error in way you want
           * @param stack
           * @return
          public static String formateException(StackTraceElement[] stack) {
               String formatedException = "";
               for (int i = 0; i < stack.length; i++) {
                    System.err.println(stack.getClassName() + ""
                              + stack[i].getMethodName() + "" + stack[i].getClass()
                              + " Line" + stack[i].getLineNumber());
                    formatedException = formatedException.concat(
                              stack[i].getClassName()
                              + "."
                              + stack[i].getMethodName()
                              + " "
                              + stack[i].getClass()
                              /** + " Line" + stack[i].getLineNumber() */
                              + "\n"); // remove comment and recieve errors line
                                             // numbers
               return formatedException;
          * showException return JOptionPane with formatted error
          * @param com
          * @param exceptionText
          public static void showException(Component com, String exceptionText) {
               JPanel canva = new JPanel();
               canva.setMinimumSize(new Dimension(300, 200));
               canva.setPreferredSize(new Dimension(300, 200));
               JTextArea area = new JTextArea();
               area.setText(exceptionText);
               JScrollPane pan = new JScrollPane();
               pan.getViewport().setView(area);
               canva.setLayout(new BorderLayout());
               canva.add(pan);
               JOptionPane.showMessageDialog(com, canva, "Error Title",
                         JOptionPane.ERROR_MESSAGE);