Additional Notes
Why avoid mutable fields in equals and hashCode?
Track: Java
Topic: Core Java
Focus: equals and hashCode in Collections
Java: equals and hashCode in Collections
Answer
They can change object state, leading to retrieval issues.
Using mutable fields in equals and hashCode can cause objects to change state after being added to a collection, making them invisible. For example, in a HashMap, altering a key's mutable field changes its hashCode, making it unreachable in the map.
Using mutable fields in equals and hashCode can cause objects to change state after being added to a collection, making them invisible. For example, in a HashMap, altering a key's mutable field changes its hashCode, making it unreachable in the map.
Topics: Core Java equals and hashCode in Collections Java