类类型转化
class ClassA{
String name = "ClassA";
}
class ClassB extends ClassA { //ClassB是ClassA的子类
String name="ClassB";
}
class AccessTest {
void test( ) {
ClassB b=new ClassB( );
System.out.println (b.name); //打印: ClassB
ClassA a;
a=(ClassA)b;
System.out.println (a.name); //打印: ClassA
}
}
class Test{
public static void main(String[] args)
{
AccessTest at=new AccessTest();
at.test();
}
}
问题:为什么第二个打印出来是:ClassA