由浅入深的介绍JAVAse的基本编程思想

				package p2;
				import p1.A;
				public class B extends A{	
					public void mb(){
						m = m + 1;	//合法，等价于  this.m = this.m + 1;
						n = n * 2;	//合法，等价于  this.n = this.n * 2;
					}
					
					public static void main(String[] args){
						B b = new B();
						b.m = 7;	//合法
						b.n = 8;	//合法
						A a = new A();
						a.m = 9;	//合法
						a.n = 10;	//非法    	
					}
				}