[IdentityHashMap]——IdentityHashMap

//IdentityHashMap键比较地址去重，只比较地址public class identihashmap {public static void main(String[] args) {IdentityHashMap<String , String> map=new IdentityHashMap<String,String>();//常量池中的"a"map.put("a", "aas");map.put("a", "aad");System.out.println(map.size());map.put(new String("a"), "ad");//这两个是不同的地址map.put(new String("a"), "da");System.out.println(map.size());}}