Java IdentityHashMap与HashMap的区别

参考IdentifyHashMap的代码注释： * This class implements the Map interface with a hash table, using * reference-equality in place of object-equality when comparing keys (and * values). In other words, in an IdentityHashMap, two keys * k1 and k2 are considered equal if and only if * (k1==k2). (In normal Map implementations (like * HashMap) two keys k1 and k2 are considered equal * if and only if (k1==null ? k2==null : k1.equals(k2)).) 关键点： HashMap判断两个key相同条件是key1.equals(key2); 而IdentifyHashMap判断key相同的条件是key1 == key2;