多项选择题
A. The hashCode method for a given class can be used to test for object equality and object inequality for that class.
B. The hashCode method is used by the java.util.SortedSet collection class to order theelements within that set.
C. The hashCode method for a given class can be used to test for object inequality， but NOT object equality， for that class.
D. The only important characteristic of the values returned by a hashCode method is that the distribution of values must follow a Gaussian distribution.
E. The hashCode method is used by the java.util.HashSet collection class to group the elements within that set into hash buckets for swift retrieval.
单项选择题 1. public class Person { 2. private String name； 3. public Person（String name） { this.name = name； } 4. public boolean equals（Person p） { 5. return p.name.equals（this.name）； 6. } 7. } Which is true？（）
单项选择题 public class Person { private name； public Person（String name） { this.name = name； } public boolean equals（Object o） { if（ !o instanceof Person ） return false； Person p = （Person） o； return p.name.equals（this.name）； } } Which is true？（）
多项选择题 public class Key { private long id1； private long 1d2； // 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？（）