方法重载错误-“编辑器不包含主要类型”

Question

package 方法重载；

公共 class 方法重载 {

public static void main(String[] args) {
    
    System.out.println("Area of rectangle: "+area(14.25d, 10.65d));
    System.out.println("Area of square: "+area(5.0d));
    }
public static double area(double length, double width){
    return length*width;
}
public static double area(double side){
    return side*side;
}
public static int area(int side){
    return side*side;
}

}