Find Missing Element From Array

package com.javatechie.solution;

import java.util.Arrays;

public class FindMissingElementFromArray {

    public static void main(String[] args) {
        int[] array={1,2,3,5};
        int n=array.length+1;
        int mid=n*(n+1)/2;
        int sum= Arrays.stream(array).sum();
        System.out.println(sum-mid);
    }
}