Additional Notes
Why do `HashSet` and `HashMap` care about `equals` and `hashCode`?
Track: Java
Topic: Collections
Focus: equals and hashCode in Collections
Java: equals and hashCode in Collections
Answer
They use those methods to decide sameness and where items belong internally.
Hash-based collections do not know your domain identity on their own. If two `Product` objects should count as the same because they share a SKU, `equals` and `hashCode` must express that rule consistently.
Hash-based collections do not know your domain identity on their own. If two `Product` objects should count as the same because they share a SKU, `equals` and `hashCode` must express that rule consistently.
Topics: Collections equals and hashCode in Collections Java