public static URL getResource(String resourceName,
    Class callingClass) 
{
        URL url = Thread.currentThread().getContextClassLoader().getResource(resourceName);
        if (url == null) {
            url = ClassLoaderUtil.class.getClassLoader().getResource(resourceName);
        }
        if (url == null) {
            ClassLoader cl = callingClass.getClassLoader();
            if (cl != null) {
                url = cl.getResource(resourceName);
            }
        }
        if ((url == null) && (resourceName != null) && (resourceName.charAt(0) != '/")) {
            return getResource('/" + resourceName, callingClass);
        }
        return url;
}

Load a given resource. This method will try to load the resource using the following methods (in order):
• From Thread.currentThread().getContextClassLoader()
• From ClassLoaderUtil.class.getClassLoader()
• callingClass.getClassLoader()

 public static InputStream getResourceAsStream(String resourceName,
    Class callingClass) 
{
        URL url = getResource(resourceName, callingClass);
        try {
            return (url != null) ? url.openStream() : null;
        } catch (IOException e) {
            return null;
        }
}

This is a convenience method to load a resource as a stream. The algorithm used to find the resource is given in getResource()

 public static Iterator getResources(String resourceName,
    Class callingClass,
    boolean aggregate) throws IOException 
{
         AggregateIterator< URL > iterator = new AggregateIterator< URL >();
         iterator.addEnumeration(Thread.currentThread().getContextClassLoader().getResources(resourceName));
         if (!iterator.hasNext() || aggregate) {
             iterator.addEnumeration(ClassLoaderUtil.class.getClassLoader().getResources(resourceName));
         }
         if (!iterator.hasNext() || aggregate) {
             ClassLoader cl = callingClass.getClassLoader();
             if (cl != null) {
                 iterator.addEnumeration(cl.getResources(resourceName));
             }
         }
         if (!iterator.hasNext() && (resourceName != null) && (resourceName.charAt(0) != '/")) {
             return getResources('/" + resourceName, callingClass, aggregate);
         }
         return iterator;
}

Load all resources with a given name, potentially aggregating all results from the searched classloaders. If no results are found, the resource name is prepended by '/' and tried again. This method will try to load the resources using the following methods (in order):
• From Thread.currentThread().getContextClassLoader()
• From ClassLoaderUtil.class.getClassLoader()
• callingClass.getClassLoader()

 public static Class loadClass(String className,
    Class callingClass) throws ClassNotFoundException 
{
        try {
            return Thread.currentThread().getContextClassLoader().loadClass(className);
        } catch (ClassNotFoundException e) {
            try {
                return Class.forName(className);
            } catch (ClassNotFoundException ex) {
                try {
                    return ClassLoaderUtil.class.getClassLoader().loadClass(className);
                } catch (ClassNotFoundException exc) {
                    return callingClass.getClassLoader().loadClass(className);
                }
            }
        }
}

Load a class with a given name. It will try to load the class in the following order:
• From Thread.currentThread().getContextClassLoader()
• Using the basic Class.forName()
• From ClassLoaderUtil.class.getClassLoader()
• From the callingClass.getClassLoader()