hashCode() method when equals() is based on multiple independent fields

Question

i have a class whose equality is based on 2 fields such that if either one is equal then the objects of this type are considered equal. how can i write a hashCode() function for

Answer 1

The simplest route is to XOR the hashcodes of each individual field. This has minor ugliness in some situations (e.g. in X,Y coordinates, it causes the potentially poor situation of having equal hashes when you flip X and Y), but is overall pretty effective. Tweak as needed to reduce collisions if necessary for efficiency.