For what purposes is method hashCode overridden in a data class?

Overriding the hashCode method in a data class is necessary for the correct functioning of objects in hash-based collections such as HashMap, HashSet, and others.

Main goals:

• Ensure that equal objects (according to equals) have the same hash code.
• Improve performance when searching, inserting, and deleting objects in hash structures.

Without proper overriding of hashCode, objects may be handled incorrectly in collections, leading to errors or data loss.

Example of overriding:

@Override
public int hashCode() {
    return Objects.hash(field1, field2);
}