public static MessageFactories getFactory(Class<? extends Map<?, ?>> mapType)
        {
            return mapType.getName().startsWith("java.util") ?
                    MessageFactories.valueOf(mapType.getSimpleName()) :
                    null;
        }
Returns the message factory for the standard jdk {@link Map} implementations.
protostuff-collectionschema/src/main/java/io/protostuff/MapSchema.java