public class TestCircle { 
  public static void main(String[] args) { 
    Circle spot = new Circle(); 
 
    spot.setRadius(5);
 
    System.out.println("Circle radius:" + spot.getRadius());
    System.out.println("Circle area: " + spot.area()); 
 
  }
}

/** 
 * Circle class.
 */
public class Circle {
  private static final double PI = 3.14;
  private double radius; 
 
  /** 
   * constructor 
   * pre: none
   * post: A circle object created. Radius initialized to 1.
   */ 
  public Circle() {
      radius = 1;          //default radius
  } 
 
 
  /** 
   * Changes the radius of the circle.
   * pre: none
   * post: radius has been changed.
   */ 
  public void setRadius(double newRadius) { 
    radius = newRadius; 
  } 
 
 
  /**
   * Calculates the area of the circle. 
   * pre: none
   * post: The area of the circle has been returned.
   */ 
  public double area() { 
    double circleArea; 
 
    circleArea = PI * radius * radius; 
    return(circleArea);
  } 
 
 
  /**
   * Returns the radius of the circle.
   * pre: none
   * post: The radius of the circle has been returned
   */ 
  public double getRadius() {
    return(radius);
  }
}

javac Circle.java TestCircle.java
java TestCircle