What are the advantages of immutability ?

Advantages of immutable classes / object

1. Immutable objects are automatically thread-safe, the overhead caused due to use of synchronisation is avoided.
2. Once created the state of the immutable object can not be changed so there is no possibility of them getting into an inconsistent state.
3. The references to the immutable objects can be easily shared or cached without having to copy or clone them as there state can not be changed ever after construction.
4. The best use of the immutable objects is as the keys of a map.