Question

Is it possible to serialize a TreeMap with a comparator??

I’ve tested and it serializes well a treemap without comparator, when you add the comparator, it throws an exception.

If I declare comparator as transient, it still doesn’t work. It only works if I make every tree map transient but it doesnt serialize the trees in that case.

Answer 1

All the classes which you attempt to serialize must implement the java.io.Serializable interface. Also, each member variable in your class should be Serializable. In fact, your whole hierarchy should be.