为什么没有报错，但一点编译就会出现之前上一个代码的运行结果，求各位大神指点？

Question

public class Shape {
void draw() {

}
void erase() {

}

}

public class Circle extends Shape{
@Override
void draw() {
System.out.println("Circle.draw()");
}
@Override()
void erase() {
System.out.println("Circle.erase()");
}
}

public class Spuare extends Shape{
@Override
void draw() {
System.out.println("Square.draw()");
}
@Override()
void erase() {
System.out.println("Square.erase()");
}
}

public class Triangle extends Shape{
@Override
void draw() {
System.out.println("Triangle.draw()");
}
@Override()
void erase() {
System.out.println("Triangle.erase()");
}
}

public class BindingTester{
public static void main(String[] args) {
Shape[] shape = new Shape[9];
int n;
for(int i = 0; i < shape.length; i++) {
n = (int)(Math.random() * 3);
switch(n) {

case 0: shape[i] = new Circle(); break;
case 1: shape[i] = new Square(); break;
case 2: shape[i] = new Triangle();
}
}

for(int i=0;i<shape.length;i++) {
shape[i].draw();
}
}
}

Answer 1

其他 先不说 n = (int)(Math.random() * 3);*3是什么鬼，不应该%3么