你学会了吗

class Color {

}

class Red extends Color {

}

class Yellow extends Color {

}

class Blue extends Color {

}

public class ColorDemo {
public static void main(String[] args) {
Color color[] = { new Red(), new Yellow(), new Blue() };
for (int i = 0; i < 3; i++) {
int index = (int) (Math.random() * 3);
judge(color[index]);
}
}

public static void judge(Color color) {
    if (color instanceof Red)
        System.out.print("红");
    if (color instanceof Yellow)
        System.out.print("黄");
    if (color instanceof Blue)
        System.out.print("蓝");
}

}