for java , we are getting input as list type array so our code will be a bit different than the simple array, code will be like this if you find any correction please let me know too.

public static int simpleArraySum(List<Integer> ar) {
    int sum = 0;
    for(int i=0; i<ar.size();i++)
         {
            sum+=ar.get(i);
         }
        return sum;
    }