title: Small problem while using JOptionPane
body: <p>I'm using JOptionPane.showMessageDialog(null,e,"Invalid Name",JOptionPane.ERROR_MESSAGE) method to display the exception extended from Exception class.
  But the Pop window is not getting displayed unless and until I press Alt+tab. What can be the reason? Below is the snippet. Suggest me something.</p>
  
  <pre><code>import java.awt.event.*;
  import java.awt.*;
  import javax.swing.*;
  import java.util.*;
  import java.io.*;
  
  class NameInvalidException extends Exception {
      /**
       * Invalid Name
       */
      String invName;
  
      public NameInvalidException() {
          super();
      }
  
      public NameInvalidException(String s) {
          invName = s;
      }
  
  }
  
  class SmallException extends Exception {
      /**
       * Short Name
       */
      String sName;
  
      public SmallException() {
          super();
      }
  
      public SmallException(String s) {
          sName = s;
      }
  
  }
  
  public class ValidName {
      public static void main(String arr[]) {
          try {
              BufferedReader br = new BufferedReader(new InputStreamReader(
                      System.in));
              System.out.println("Enter the name: ");
  
              String name = br.readLine();
              checkName(name);
          } catch (IOException e) {
              System.out.println(e);
          }
  
      }// end main
  
      static void checkName(String name) {
  
          try {
  
              String sarr[] = name.split(" ");
              if (sarr.length != 3)
                  throw new SmallException(name);
              for (int j = 0; j &lt; 3; j++) {
                  System.out.println("in j loop");
                  if (sarr[j].length() &lt; 3) {
                      throw new SmallException();
                  }
              }
              for (int i = 0; i &lt; name.length(); i++) {
  
                  char ch = name.charAt(i);
                  if (Character.isLetter(ch) || Character.isWhitespace(ch))
                      System.out.println("ok " + ch);
                  else
                      throw new NameInvalidException();
  
              }// end for
          }// end try
          catch (NameInvalidException e) {
              JOptionPane.showMessageDialog(null, e.toString(), "Invalid Name",
                      JOptionPane.ERROR_MESSAGE);
              System.out.println(e);
          } catch (SmallException es) {
              JOptionPane.showMessageDialog(null, es.toString(), "Invalid Name",
                      JOptionPane.ERROR_MESSAGE);
  
          }
      }// end checkName(name)
  }
  </code></pre>