JAVA 编程，编写一个名为Stock的Java子类，继承自父类Item，并实现了具有以下特性的类似接口，详细在图？

~ 按照题目要求编写的Stock子类的Java程序如下
public class Stock extends Item implements Comparable<Stock>{
private String location;
private int qty;
public Stock(String goods,int unitperbox,String location,int qty){
super(goods,unitperbox);
this.location=location;
this.qty=qty;
}
public int compareTo(Stock a){
if(a.ShowUnitPerBox()*a.ShowQty()==super.ShowUnitPerBox()*this.ShowQty()){
return 0;
}else if(a.ShowUnitPerBox()*a.ShowQty()<super.ShowUnitPerBox()*this.ShowQty()){
return 1;
}else{
return -1;
}
}
public String ShowLocation(){
return this.location;
}
public int ShowQty(){
return this.qty;
}
public int Total(){
return super.ShowUnitPerBox()*this.ShowQty();
}
}