試題詳解

A programmer is developing a class Key, that will be used as a key in a standard java.util.HashMap. Which two methods should be overridden to assure that Key works correctly as a key? (Choose two.)
(A) public int hashCode()
(B) public void hashCode()
(C) public int compareTo(Object o)
(D) public boolean equals(Object o)
(E) public boolean compareTo(Key k)