public static InputStream getResourceAsStream(String resource,
                                                  Class<?>... classes) {
        return getResourceAsStream(resource, false, classes);
    }
Retrieves the resource as an input stream via the context class loader of the current thread,
and if not found, via the class loaders of the optionally specified classes in the order of
their specification, and if not found, from the class loader of {@link ClassLoaderHelper} as
the last resort.

@param resource
           resource to be loaded
@param classes
           class loader providers
@return the resource loaded as an input stream or null if not found.
aws-java-sdk-code-generator/src/main/java/com/amazonaws/codegen/internal/ClassLoaderHelper.java