自己做的demo---宣告可以在java世界开始自由了

 package $interface;

 public interface ILeaveHome {
     public abstract int a();
     public abstract int b();
     public abstract int c();
     public abstract int d();

 }

 package $interface;

 public abstract class AbstractTools {
     private String abs01;//private的要设置访问器，外部的才可以访问
     private String abs02;
     public AbstractTools(String abs01,String abs02)
     {
         this.abs01=abs01;
         this.abs02=abs02;
     }

     public void tools1() {
         System.out.println("zzw abstract");
     }
     public abstract int tool2();

     public void setAbs01(String abs01)
     {
         this.abs01=abs01;
     }
     public String getAbs01()
     {
         return abs01;
     }
     public void setAbs02(String abs02)
     {
         this.abs02=abs02;
     }
     public String getAbs02()
     {
         return abs02;
     }
 }

 package $interface;

 public class LeaveHomeImpl extends AbstractTools implements ILeaveHome{

     public LeaveHomeImpl(String a,String b){
         super(a, b);//调用父类的构造方法

     }
     public int  tool2(){
         int a=6666;
         return a;

     }
     public int a(){
         int a=1;
         return a;
     }
     public int b(){
         int b=1;
         return b;
     }
     public int c(){
         int c=1;
         return c;
     }
     public int d(){
         int d=1;
         return d;
     }

     public static void main(String args[])
     {
         String z="z";
         String z6="z6";
         LeaveHomeImpl home=new LeaveHomeImpl(z,z6);
         System.out.println("home.a()="+home.a());
         System.out.println("home.b()="+home.b());
         System.out.println("home.c()="+home.c());
         System.out.println("home.d()="+home.d());
         System.out.println("home.tool2()="+home.tool2());
         System.out.println("getAbs01="+home.getAbs01());
         System.out.println("getAbs02="+home.getAbs02());
         home.tools1();

     }

 }

 package $interface;

 public class LeaveHomeTwice extends LeaveHomeImpl{
     String a;
     String b;

     public LeaveHomeTwice(){//第一种构造方式,

         super("a","b");//传值进去的时候会自动调用父类的有参数的构造方法

     }
     public LeaveHomeTwice(String a,String b){//带参数的构造方法，体现了构造方法的overload，构造方法的重载

         super(a,b);//改变了父类的值

     }
     //方法的override，方法的覆盖，对父类的覆盖
     public int  tool2(int a){

         int  zzw;
         zzw=a;
         return zzw;

     }

     public static void main(String args[])
     {
         int num=123;
         LeaveHomeTwice a=new LeaveHomeTwice();//对应第一种构造方式
         //LeaveHomeTwice a=new LeaveHomeTwice("zzwtwice","aiguotwice");//对应第二种构造方式
         System.out.println(a.a()+"\t"+a.b()+"\t"+a.c()+"\t"+a.d()+"\t"+a.tool2(num));

         a.tools1();
         System.out.println("getAbs01:"+a.getAbs01());
         System.out.println("getAbs02:"+a.getAbs02());

     }

 }