1 Reply Latest reply on Jun 1, 2011 11:09 AM by panchonb

    URL getContent returns Virtual File instead of ImageProducer in JBoss AS 6.0.0

    panchonb Newbie


      We have been tasked to move from JBoss 4.2.3GA to JBoss AS 6.0.0.FINAL.  We have run into an issue where a thirdparty component is throwing a NullPointer exception.


      We traced this exception down to a resource file (image) not working anymore.  In JBoss 4.2.3.GA this would work fine, but now in JBoss 6 it doesn't.

      After finding that the Image was now null, we again did more digging.  Turns out it is a change in how URL.getContent works.


      If the image is loaded in a normal Java environment outside of JBoss, the image works fine and the reference to the image is non-null.  When we then use the same exact class, in the same exact Jar but in JBoss, the image gets set to null.


      Here is an example that works from a straight up Java environment, but not in JBoss:


      package example.loadimage.fail;
      import java.awt.Image;
      import java.beans.SimpleBeanInfo;
      public class LoadImageTest extends SimpleBeanInfo {
                public Image image;
                public LoadImageTest(){
                          image = loadImage2("icon.png");
                 * @param args
                public static void main(String[] args) {
                          LoadImageTest test = new LoadImageTest();
                          System.out.println("Is image null? " + (test.image == null));
                // Note: This method was pulled out of the JDK src file for SimpleBeanInfo.java.
                // This allows for easier debugging, you can actually see the local variables.
                public java.awt.Image loadImage2(final String resourceName) {
                          try {
                              final Class c = getClass();
                              java.awt.image.ImageProducer ip = (java.awt.image.ImageProducer)
                                    new java.security.PrivilegedAction() {
                                        public Object run() {
                                              java.net.URL url;
                                              if ((url = c.getResource(resourceName)) == null) {
                                                  return null;
                                              } else {
                                                  try {
                                                        return url.getContent();
                                                  } catch (java.io.IOException ioe) {
                                                        return null;
                              if (ip == null)
                                    return null;
                              java.awt.Toolkit tk = java.awt.Toolkit.getDefaultToolkit();
                              return tk.createImage(ip);
                          } catch (Exception ex) {
                                   // will end up here because the PrivilegedAction returns something that cannot be cast
                                   // to an ImageProducer when this is run in JBoss AS 6.0.0.FINAL. In JBoss the returned
                                   // object will be a VirtualFile instead of an ImageProducer. 
                              return null; 



      This class will print out false when run from the main method, meaning the image member is not null.


      Here is a JSP that will print true because the image is now null:


      <%@page import=" example.loadimage.fail.LoadImageTest"%>

      <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>



      <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">



      <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">

      <title>Insert title here</title>




      out.print("Testing<br />");

      LoadImageTest test = new LoadImageTest();

      out.print("Is test.image null? " + (test.image == null) + "<br />");






      This seems to be a change in how an image is returned.  Instead of returning an ImageProducer from the url.getContent() method, it returns a VirtualFile.  Hence, the reason for the ClassCastException which is then swallowed and a null value returned.


      Please, note that the loadImage2(...) method is taken directly from the JDK src of SimpleBeanInfo.java.  It was extracted to ease debugging.


      Is this a bug in JBoss?  Or is there something we are missing?  Modification of the third party component is a last resort we don't really want to do.


      Hope this make sense.