Question

java 中 Map 内部是怎么实现的

Answer 1

Map只是一个接口，只定义了具体的方法，没有去实现任何功能的
Map的源码如下：
public abstract interface Map<K, V>
{
public abstract int size();

public abstract boolean isEmpty();

public abstract boolean containsKey(Object paramObject);

public abstract boolean containsValue(Object paramObject);

public abstract V get(Object paramObject);

public abstract V put(K paramK, V paramV);

public abstract V remove(Object paramObject);

public abstract void putAll(Map<? extends K, ? extends V> paramMap);

public abstract void clear();

public abstract Set<K> keySet();

public abstract Collection<V> values();

public abstract Set<Entry<K, V>> entrySet();

public abstract boolean equals(Object paramObject);

public abstract int hashCode();

public static abstract interface Entry<K, V>
{
public abstract K getKey();

public abstract V getValue();

public abstract V setValue(V paramV);

public abstract boolean equals(Object paramObject);

public abstract int hashCode();
}
}

Answer 2

楼下回答正确，map只是接口，实现类有很多
HashMap，HashTable,LinkedHashMap.....