How to randomize (shuffle) java code example

Example 1: how to randomize an array java

void shuffle(int [] arr) {
        for (int i = 0; i < arr.length; i++) {
            int index = (int) (Math.random() * arr.length);
            int temp = arr[i];
            arr[i] = arr[index];
            arr[index] = temp;
        }
    }

Example 2: random suffling java

for (int i = myList.length - 1; i > 0; i--){
            int j = (int) (Math.random() * (i + 1));

            double temp = myList[i];
            myList[i] = myList[j];
            myList[j] = temp;
        }