/**
 * Created by whp on 2018/7/30.
 */
public class Test {
    public static void main(String[] args) {
    String[] str={"象牙海岸","阿根廷","澳大利亞","塞爾維亞","荷蘭","奈及利亞","日本",
            "美國","中國","紐西蘭","巴西","比利時","韓國","喀麥隆","宏都拉斯","義大利"};
        List list=new ArrayList();
        List list1=new ArrayList();
        for
 
(int i=0;i<str.length;i++){
            list.add(str[i]);
        }
        while(true){
            list1.clear();
            while (true) {
                Random random = new Random();
                int index = random.nextInt(list.size());
                Object s = list.get(index);
                list1.add(s);
                list.remove(index);
                if
 
 (list1.size() == 4) {
                    for (Object o : list1) {
                        System.out.print(o + " ");
                    }
                    break;
                }
            }
            System.out.println();
            if (list.size() == 0) {
                break;
            }
        }
    }
}