About Question enthuware.ocpjp.v7.2.1515 :

[boyonsea]

Not sure if the answer provided is correct.
It assumes that the user has overridden the hashcode and equals method correctly.

[admin]

This is a general statement about equals and hashCode contract. Even so, the problem statement does contain thisat the bottom, "(Assume that the equals and hashCode contract is not violated by the class.)".\