package my_first_java;
import java.util.Random;
/*****
 * 洗牌算法
 * @author xiang
 *
 */
public class MyFirstJava {

    public static void main(String[] args) {
        String [] cards = {"黑桃A","红桃2","梅花7","梅花7","方块10","黑桃9"};
        Ramdom r = new Random();
        for(int i=cards.length-1; i>=1; i--){
            int j = r.nextInt(i);//j=[0,i)
            String t = cards[i];
            cards[i] = cards[j];
            cards[j] = t;
        }
        
        System.out.println("My first Java program!");// TODO Auto-generated method stub
        System.out.print(cards);
    }

}


编译报错：
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
    Ramdom cannot be resolved to a type

    at my_first_java.MyFirstJava.main(MyFirstJava.java:12)

哎，低级错误，谢谢楼上