What is @EqualsAndHashCode used for?

@EqualsAndHashCode generates proper equals() and hashCode() overrides based on the class's fields, following the standard contract Java expects — two objects with equal field values are considered equal and produce the same hash code, which is essential for correct behavior in collections like HashSet or HashMap.

@EqualsAndHashCode
public class Point {
    private int x;
    private int y;
}
//  two Point(1, 2) instances are now equal, and share the same hashCode

By default it includes all non-static fields, but specific fields can be excluded with @EqualsAndHashCode.Exclude — useful for fields that shouldn't factor into equality, such as a timestamp or a cached, derived value that doesn't represent the object's actual identity.

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