java内存泄漏问题

 Static Vector v = new Vector(10); 
 for (int i = 1; i<100; i++) 
 { 
 Object o = new Object(); 
 v.add(o); 
 o = null; 
 }

public static void main(String[] args) 
{ 
Set<Person> set = new HashSet<Person>(); 
Person p1 = new Person("唐僧","pwd1",25); 
Person p2 = new Person("孙悟空","pwd2",26); 
Person p3 = new Person("猪八戒","pwd3",27); 
set.add(p1); 
set.add(p2); 
set.add(p3); 
System.out.println("总共有:"+set.size()+" 个元素!"); //结果：总共有:3 个元素! 
p3.setAge(2); //修改p3的年龄,此时p3元素对应的hashcode值发生改变 
 set.remove(p3); //此时remove不掉，造成内存泄漏
 set.add(p3); //重新添加，居然添加成功 
 System.out.println("总共有:"+set.size()+" 个元素!"); //结果：总共有:4 个元素! 
 for (Person person : set) 
 { 
 System.out.println(person); 
 } 
 }