java 中常见的java.lang.ClassCastException - 代码共享

[代码] [Java]代码 package cn.itcast.apsliyuan.text;

public class TypeDemo {
	public static void main(String[] args) {
		A a1=new A();
		A a2=new B();
		A b=a1;
		//C c=(C) a2;这句话会发作java.lang.Class http://www.fpnanchang.com/linked/20130210.do; CastException 反常，只能向上转型，
	}
}

class A{
	
}
class B extends A{
	
}
class C extends A{
	
} http://www.fpshijiazhuang.com/linked/20130210.do;