下面哪个选项没有实现 java.util.Map 接口?
//直接看源码的定义 public class Hashtable<K,V> extends Dictionary<K,V> implements Map<K,V>, Cloneable, java.io.Serializable public class HashMap<K,V> extends AbstractMap<K,V> implements Map<K,V>, Cloneable, Serializable public class Vector<E> extends AbstractList<E> implements List<E>, RandomAccess, Cloneable, java.io.Serializable public class IdentityHashMap<K,V> extends AbstractMap<K,V> implements Map<K,V>, java.io.Serializable, Cloneable
public class Hashtable<K,V> extends Dictionary<K,V> implements Map<K,V>, Cloneable, java.io.Serializable {
public class HashMap<K,V> extends AbstractMap<K,V> implements Map<K,V>, Cloneable, Serializable {
public class Vector<E> extends AbstractList<E> implements List<E>, RandomAccess, Cloneable, java.io.Serializable {
public class IdentityHashMap<K,V> extends AbstractMap<K,V> implements Map<K,V>, java.io.Serializable, Cloneable {