//try to find classes dirs inside war files
urlSet = urlSet.includeClassesUrl(classLoaderInterface);
urlSet = urlSet.excludeJavaExtDirs();
urlSet = urlSet.excludeJavaEndorsedDirs();
try {
urlSet = urlSet.excludeJavaHome();
} catch (NullPointerException e) {
// This happens in GAE since the sandbox contains no java.home directory