類的繼承小例子

public class Test {
	public static void main(String[] args) {
		Person p = new Student();
		Teacher t = new Teacher();
		Student s = new Student();
		if(t instanceof Person){p = t;}
		if(s instanceof Person){s = (Student)p;}
	}
}

Exception in thread "main" java.lang.ClassCastException: Teacher cannot be cast to Student

at Test.main(Test.java:8)

if(s instanceof Person){s = (Student)p;}

編譯時出錯