This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
equals() using to comparison, refers to equivalence relations. hashCode() is id number allocated to an object by JVM. Contract: When you use equals() and hashCode() methods is necessary to override these methods