1）设计一个形状类Shape，包含一个getArea()方法，该方法不包含实际语句。

不怎么明白题意，随便写一个public interface ShapePara {public int getArea();//获得图形的面积public int getCircumference();//获得图形的周长}public class Circle implements ShapePara {public double radius;//圆的半径private double x;//圆心的横坐标protected double y;//圆心的纵坐标public Circle(double radius) {super();this.setRadius(radius);this.setCenter(0.00, 0.00);}@Overridepublic int getArea() {return (int) (Math.PI*Math.pow(radius, 2));}@Overridepublic int getCircumference() {return (int) (Math.PI*2*radius);}//获取半径public double getRadius(){return this.radius;}//设置圆心坐标public void setCenter(double x, double y){this.x = x;this.y = y;}//设置radius域public void setRadius(double radius){this.radius = radius;}public static void main(String[] args) {Circle circle = new Circle(5.00);}}