What is hashcode collision? - Cracking the Java Coding Interview #javalanguage #javacoding #javatips

A hash code collision occurs when two different objects share the same hash code. Since hash codes are 32-bit integers, collisions are mathematically inevitable given the vast number of possible objects. The Java spec requires equal objects to have equal hash codes, but not vice versa. Collisions can degrade performance: a HashSet's contains() operation can degrade from O(1) to O(log n). Additionally, too many collisions can prevent proper splitting of sets in parallel streams, potentially hurting rather than improving performance.