How to compile packages in Java

Let us look at an example that creates a package called animals. It is a good practice to use names of packages with lower case letters to avoid any conflicts with the names of classes and interfaces.

Following package example contains interface named animals −

/* File name : Animal.java */
package animals;
interface Animal {
   public void eat();
   public void travel();
}

Now, let us implement the above interface in the same package animals −

package animals;
/* File name : MammalInt.java */
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();
   }
}

Now compile the java files as shown below −

$ javac -d . Animal.java
$ javac -d . MammalInt.java

Now a package/folder with the name animals will be created in the current directory and these class files will be placed in it as shown below.