import java.util.*;
public class shuffle {
    public static void main(String[] args) {
        ArrayList<Integer> test = new ArrayList<Integer>();
        test.add(1);
        test.add(5);
        test.add(20);
        test.add(14);
        System.out.println(test);
        shuffle1(test);
        System.out.println(test);
    }

    public static void shuffle1(ArrayList<Integer> list1){
        Random randomGenerator = new Random();
        int listSize = list1.size();
        for (int i = 0; i < list1.size(); i++){
            int j = 0;
            while (i <= j){
                j = randomGenerator.nextInt(listSize);
            }
            swap(list1, i, j);
        }
    }

    public static void swap(ArrayList<Integer> list, int i, int j){
        int temp = list.get(i);
        list.add(i, list.get(j));
        list.add(j, temp);

    }
}