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Java / Map and its implementations

Does IdentityHashMap use hashcode method?

No. IdentityHashMap does not use hashCode method instead it uses System.identityHashCode() method. It neither use equals method instead uses == reference equality operator.

IdentityHashMap class is not a general-purpose Map implementation; it intentionally violates Map's general contract to use equals method when comparing objects.

This class is designed for use only in the rare case scenario where reference-equality semantics are required.

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Set and its implementations

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