HashSet中remove方法的坑

public class CollectionTest {

   @Test
   public void test3(){
	   HashSet set = new HashSet();
	   Person p1 = new Person(1001,"AA");
	   Person p2 = new Person(1002,"BB");

	   set.add(p1);
	   set.add(p2);
	   System.out.println(set);    
	  //输出2个值[person={1001,"AA"},person={1002,"BB"}]

	  p1.name = "CC";
	  set.remove(p1);
	  System.out.println(set);
	  //输出两个值[person={1001,"CC"},person={1001,"BB"}]
  
	  set.add(new Person(1001,"CC"));
	  System.out.println(set);
	  //输出三个值  [person={1001,"CC"},person={1002,"BB"},person={1001,"CC"]

	  set.add(new Person(1001,"AA"));
	  System.out.println(set);
	  //输出四个值 [person={1001,"CC"},person={1002,"BB"},person={1001,"CC"，person={1001,"AA"]
	  
  }
}  

那么出现这种原因:
    主要是由于Set类中remove元素是依据“哈希值”来删除元素
	Set类添加元素的规则:
	    1.比较哈希值,当哈希值相同就使用equals()方法来判断,相同删掉,不同则添加
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那么以上remove无法删除元素的现象，我们只需重写HashCode方法,即可实现元素删除的效果,
    可完美的避免此坑