Class.getResource JNLP issue

Question

I'm seeing an error when deploying an application via JNLP:
schema_reference.4: Failed to read schema document 'jar:com/mycompany/my_schema.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>On a Linux machine, running 1.5.0_15-b04, it works fine. On a Windows machine, running 1.5.0_16-b02, it fails.
The code is attempting to load an XSD as follows (and is failing on the second line):
  URL schemaURL = MyClass.class.getResource("my_schema.xsd");
  SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema(schemaURL);On the Linux machine, where it works, the URL returned from the "getResource" call looks like:
jar:file:/path/to/containing.jar!/com/mycompany/my_schema.xsd
On the Windows machine, where it fails, the URL returned from the "getResource" call looks like:
jar:com/mycompany/my_schema.xsd
The same JARs are being run via JNLP on both machines.
I found that getting an InputStream instead of an URL (via MyClass.class.getResourceAsStream("my_schema.xsd")) and passing that into the newSchema call with a new StreamSource works if the schema is completely self-contained. However, one schema I work with is extremely large and is broken into many different files via "<xs:include schemaLocation=""/>". This schema does not appear to load correctly via getResourceAsStream.
I suspect this may be a classloader issue inside JNLP. When I run the application using the same JARs via javaw on the Windows machine, everything works.
What am I doing wrong and how do I go about working around/fixing this issue?
Thanks,
--David                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

Here is some code that works around the issue:
    public static URL getResource(Class clazz, String name) {
        // Get the URL for the resource using the standard behavior
        URL result = clazz.getResource(name);
        // Check to see that the URL is not null and that it's a JAR URL.
        if (result != null && "jar".equalsIgnoreCase(result.getProtocol())) {
            // Get the URL to the "clazz" itself.  In a JNLP environment, the "getProtectionDomain" call should succeed only with properly signed JARs.
            URL classSourceLocationURL = clazz.getProtectionDomain().getCodeSource().getLocation();
            // Create a String which embeds the classSourceLocationURL in a JAR URL referencing the desired resource.
            String urlString = MessageFormat.format("jar:{0}!/{1}/{2}", classSourceLocationURL.toExternalForm(), packageNameOfClass(clazz).replaceAll("\\.", "/"), name);
            // Check to see that new URL differs.  There's no reason to instantiate a new URL if the external forms are identical (as happens on pre-1.5.0_16 builds of the JDK).
            if (urlString.equals(result.toExternalForm()) == false) {
                // The URLs are different, try instantiating the new URL.
                try {
                    result = new URL(urlString);
                } catch (MalformedURLException malformedURLException) {
                    throw new RuntimeException(malformedURLException);
        return result;
    public static String packageNameOfClass(Class clazz) {
        String result = "";
        String className = clazz.getName();
        int lastPeriod = className.lastIndexOf(".");
        if (lastPeriod > -1) {
            result = className.substring(0, lastPeriod);
        return result;
    }There are two additional work-arounds:
1. Use Class.getResourceAsStream(String). However this doesn't work in the case of XSDs that use <xs:include> to include other XSDs via relative pathing.
2. A real hack: Class.getResource("MyResource.txt").openConnection().getURL().