CareerCup

You must override hashcode method, whenever you override equals method, as the best practice (though your program will get compiled & run, even without this). May be that's what the interviewer was expecting to hear back, as part of response to this question.

implement the comparable interface!

comapre interface,comparator class, equals and hashcode methods also used for this purpose. Finally you can use == operator to compare references by identity.

comapre interface,comparator class, equals and hashcode methods also used for this purpose. Finally you can use == operator to compare references by identity.

You can override equals method to compare two objective

You can override equals method to compare two objective

You can implement Comparable or use a Comparator. Following is an example where we want to compare two accounts based on balance.

public class Account implements Comparable<Account>{
    @Override
    public int compareTo(Account account) {
        return (this.balance < account.balance ) ? -1: (this.balance > account.balance ) ? 1:0 ;
    }
}

public class AccountBalanceComparator implements Comparator<Account>{

    @Override
    public int compare(Account accountA, Account accountB) {
        
        return (accountA.getBalance() < accountB.getBalance() ) ? -1: (accountA.getBalance() > accountB.getBalance() ) ? 1:0 ;
    }
}

Sometimes usual equals() method may work. If the objects have tree sort of structure and we need to compare all fields in methods, then 'java reflection' may work.