Generics

Collections and Generics

equals() and hashcode()

• Mainly used for storing and retrieving objects from hashed collections.
• First object's hashcode is used to figure out which hash bucket the object is in
• Then the equals() method is used to compare objects in the same hash bucket.

This means that:

• equal objects MUST have the same hashcode
• unequal objects can have the same (or different) hashcode (e.g. same bucket but objects are different)
• objects having different hashcodes MUST be unequal