override abstract method java

1public interface Order
2{
3    public boolean greaterThan(Order other);
4}
5
6public class AirCraft implements Order
7{
8   private String make;
9   private int numSeats;
10
11   public AirCraft(String make, int numSeats)
12   {
13      this.make = make;
14      this.numSeats = numSeats;
15   }
16
17   public String getMake()
18   {
19      return make;
20   }
21
22   public int getNumSeats()
23   {
24      return numSeats;
25   }
26
27   @Override
28   public boolean greaterThan(Order other)
29   {
30      AirCraft x = (AirCraft)other;
31      return getNumSeats() > x.getNumSeats();
32   }
33   
34   public String toString()
35   {
36       return make + " -> " + numSeats;
37   }
38}