hashCode() value changes between executions

Question

hashCode of an object has to be consistent for that object throughout one execution of the application-- for any object o, o.hashCode() should return the same int value.

However, this doesn't have to be from one run-time to another: o.hashCode() can return some other value and this is perfectly alright by the specs.

HashMap calculates the right bucked based on the hashCode value.

My Q is: how is this value change between one session to another handled? Does serialization have features to handle this?

So, suppose I built a hash and stored it on the disk. 2 weeks after, I invoked the application and am running it. I'm looking up an object in the hash. By these, the hashCode of this object is/can be now different than before and I wont be able to find it although it is there in the hash.

Answer 1

This works because hashtables are not serialized as hashtables. They are serialized in a custom way. So when deserialized, the hashtable will be rebuilt using the new hashcodes.