编写Java应用程序包括三类：A类、B类和主类E

编写Java应用程序包括三类：A类、B类和主类E

class A{ int a1=5;

void mA() { System.out.println("A.mA"); }

}

class B extends A {

int b1=6;

int a1=7;

void mB() { System.out.println("B.mB"); }

void mA() { System.out.println("B.mA"); }

}

public class E {

public static void main(String[] args) {

B b=new B();

A a=b;

System.out.println("b.a1="+b.a1);

System.out.println("b.b1="+b.b1);

b.mA();

b.mB();

System.out.println("a.a1="+a.a1);

a.mA();

}

}