CircleRunner.java

public class CircleRunner{
   public static void main(String[] args){
      //Instantiation of c1
      Circle c1 = new Circle();
      //Call methods on c1
      c1.setRadius(5.0);
      System.out.println( c1.circumference() );

      //Instantiation of c2
      Circle c2 = new Circle();
      //Call methods on c2
      c2.setRadius(3.0);
      System.out.println( c2.circumference() );
   }
}