Creating Multiple Classes in a Package:

In java, one program can have only one public class. If at all, there are more non-public classes in a same program, they will not become the members of a package. But, to have multiple classes in a single package, the directory is going to be same; while the classes are to be written in different programs. 

The following example shows step-by-step approach to create a package with multiple classes.

·         First create a directory by name “Arithmetic” and move to that directory

·         Create the following file (file name should be Sum.java) and compile the file in the same directory.

package arithmetic;

public class Sum

{

  public int add(int x,int y)

  {

     return x+y;

  }

}

·         Create the second file (file name should be Difference.java) and compile the file in the same directory.

package arithmetic;

public class Difference

{

  public int sub(int x,int y)

  {

     return x-y;

  }

 }

·            Now, Move to parent (working) directory, write the following file (Test.java) and execute it.

import arithmetic.*;

class Test

{

   public static void main(String as[])

   {

       Sum s1 = new Sum();

       System.out.println(s1.add(8,5));    // prints  13

       Difference d1 = new Difference ();

       System.out.println(d1.sub(8,5));     // prints  3

   }

}