java-package (example)

inf : http://www.tutorialspoint.com/java/java_packages.htm

1. the interface method cannot have body.
2.  when implements the implements must after extends.



You and other programmers can easily determine that these types are related.

/* File name : Animal.java */

package animals;

interface Animal {
   public void eat();

   public void travel();
}


/* File name : MammalInt.java */

package animals;
public class MammalInt implements Animal{

   public void eat(){
      System.out.println("Mammal eats");
   }

   public void travel(){
      System.out.println("Mammal travels");
   }

   public int noOfLegs(){
      return 0;
   }

   public static void main(String args[]){
      MammalInt m = new MammalInt();
      m.eat();
      m.travel();
   }
}

$ mkdir animals
$ javac Animal.java
$ javac MammalInt.java
$ cp Animal.class animals
$ cp MammalInt.class animals

$ java animals/MammalInt
Mammal eats
Mammal travels


but 
cd animals
java MammalInt fail