> Also, your first class isn't fully immutable—getTags should be implemented as follows: True. It would be nice if Java had some immutable collection classes t

> Also, your first class isn't fully immutable—getTags should be implemented as follows: True. It would be nice if Java had some immutable collection classes that don't have mutable methods. A method that gets a List<String> made with Collections.unmodifiableList(tags), doesn't know that it is actually immutable.