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  1. JBoss VFS
  2. JBVFS-206

URL.getContent() returns VirtualFile instead of ImageProducer

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    • Icon: Bug Bug
    • Resolution: Done
    • Icon: Major Major
    • 3.2.13.Final, 3.5.0.Alpha1
    • 3.2.12.Final
    • None
    • None
    • Workaround Exists
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      Read the content directly such as with ImageIO.read(url.openStream().getSource() 

      import java.awt.Image;
import javax.imageio.ImageIO;
import java.io.InputStream;
import java.beans.SimpleBeanInfo;

            URL url = Thread.currentThread().getContextClassLoader().getResource(resourceName);
            InputStream is = null;
            try {
               is = url.openStream();
               return ImageIO.read(is).getSource();
            } catch(Exception e) {
               e.printStackTrace();
               return null;
            } finally {
               try { is.close(); } catch(Exception e) { } 
            }
      Show
      Read the content directly such as with ImageIO.read(url.openStream().getSource() import java.awt.Image; import javax.imageio.ImageIO; import java.io.InputStream; import java.beans.SimpleBeanInfo; URL url = Thread .currentThread().getContextClassLoader().getResource(resourceName); InputStream is = null ; try { is = url.openStream(); return ImageIO.read(is).getSource(); } catch (Exception e) { e.printStackTrace(); return null ; } finally { try { is.close(); } catch (Exception e) { } }
    • Hide

      Here are an example class and a jsp to reproduce the problem:

      LoadImageTest.java
      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");
	}
	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)
			java.security.AccessController.doPrivileged(
			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;
		}
	}
}

      <%@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">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
out.print("Testing<br />");
LoadImageTest test = new LoadImageTest();
out.print("Is test.image null? " + (test.image == null) + "<br />");
%>
</body>
</html>
      Show
      Here are an example class and a jsp to reproduce the problem: LoadImageTest.java 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" ); } 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) java.security.AccessController.doPrivileged( 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 ; } } } <%@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" > <html> <head> <meta http-equiv= "Content-Type" content= "text/html; charset=ISO-8859-1" > <title> Insert title here </title> </head> <body> <% out.print( "Testing <br /> " ); LoadImageTest test = new LoadImageTest(); out.print( "Is test.image null? " + (test.image == null) + " <br /> " ); %> </body> </html>

      URL.getContent() behaves differently within JBoss than it does in a normal JVM. In our case, when a jar is used in a normal JVM, URL.getContent() returns an ImageProducer. When the same jar is used from within JBoss, a VirtualFile is returned which then causes a ClassCastException.

      Note: This worked fine in JBoss 4.2.3.GA.

              thofman Tomas Hofman
              thofman Tomas Hofman
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                Created:
                Updated:
                Resolved: