private static Class<?> map(String className, int id)
    {
        Class<?> clazz = RuntimeEnv.loadClass(className);
        __nonPublicCollections.put(clazz, id);
        return clazz;
    }
Used when the type is an interface (Collection/List/Set/SortedSet).

@author David Yu
@created Apr 24, 2012
protostuff-runtime/src/main/java/io/protostuff/runtime/PolymorphicCollectionSchema.java