单项选择题
A. Compilation fails because the hashCode method is not overridden.
B. A HashSet could contain multiple Person objects with the same name.
C. All Person objects will have the same hash code because the hashCode method is not overridden.
D. If a HashSet contains more than one Person object with name=”Fred”， then removing another person， also with name=”Fred”， will remove them all.
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？（）
单项选择题 public class Person { private String name， comment； private int age； public Person（String n， int a， String c） { name = n； age = a； comment = c； } public boolean equals（Object o） { if（! （o instanceof Person）） return false； Person p = （Person）o； return age == p.age && name.equals（p.name）； } } What is the appropriate definition of the hashCode method in class Person？（）
单项选择题 Aprogrammerhasanalgorithmthatrequiresajava.util.Listthatprovidesanefficientimplementationofadd（0，object），butdoesNOTneedtosupportquickrandomaccess.Whatsupportstheserequirements？（）