QUESTION 31

QUESTION 31 
Given: 
 
public class Key {
     private long id1;
     private long id2; 
 
    // class Key methods } 
 
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 boolean equals(Key k) 
C. public int compareTo(Object o) 
D. public boolean equals(Object o) 
E. public boolean compareTo(Key k) 
Solution : AD