java和数据结构（待续）

（一）java对象使用的常识

部分代码：

public class Student implements interface

Person p; 

Student s = new Student();

p = s; 

Person q; 

p.equalTo(q)； // Will not compile, q is not pointing to any object

p.equalTo(s) ；// Will not compile, s is not of type Person

but you can cast the object to Person mannually, so

p.equalTo((Person)s)  is fine