Multiple threads to calculate sums Java

Question

this is how I can find sum of array. p[i] - array of random integers, size 1000

sum = 0;
for (int j = 1; j < p.length; j++ ) 
    {
            sum = sum + p[j];
    }

my question is how can I use multiple threads to perform it faster?

Answer 1

Simply:

int sum = Arrays.stream(p).parallel().sum();