People p1 = new People(21,"lisi");
People p2 = new People(21,"lise");
p2= p1;
p2.setAge(1);
System.out.println(p1.getAge());
System.out.println(p2.getAge());
System.out.println(p1.equals(p2));
System.out.println(p1==p2);

class People{
int age;
String name;
        public People(int age, String name) {
                super();
                this.age = age;
                this.name = name;
        }
public int getAge() {
                return age;
        }
        public void setAge(int age) {
                this.age = age;
        }
}

结果：
1
1
true
true

建议看一下第六天的的这个视频:06.09_面向对象(三个引用两个对象的内存图).avi .答案就在里面

p2=p1就已经指向同一个地址了，以后只要不改变引用地址的话什么都一样