code: public void setCenterColor(Color color) {
          if (centerColor == null) {
              centerColor = new RGBColor(0.0, 0.0, 0.0);
          }
          setGradation(true);
          this.centerColor = color;
      }
docs: Sets the color of this Ellipse's center.
  
  @param color The color of the Ellipse's center.