Find missing integer in Java

 This is the program to find the missing numbers in the first n integers.

public static int findMissingNumber(int[] nums) {
    int n = nums.length + 1;
    // formula for sum of first n integers is n*(n+1)/2
    // but we have n+1 integers as one integer is missing
    int sum = (n * (n + 1)) / 2;
    for (int i = 0; i < nums.length; i++) {
        sum -= nums[i];
    }
    return sum;
}