Divide and conquer summing of an array using Java fork/join

ArraySumCalculator.java

import java.util.concurrent.RecursiveTask;

public class ArraySumCalculator extends RecursiveTask<Long> {
    private static final int THRESHOLD = 1000; // Threshold for splitting the array
    private final int[] array;
    private final int start;
    private final int end;

    public ArraySumCalculator(int[] array, int start, int end) {
        this.array = array;
        this.start = start;
        this.end = end;
    }

    @Override
    protected Long compute() {
        int length = end - start + 1;
        if (length <= THRESHOLD) {
            // If the array size is smaller than the threshold, compute the sum sequentially
            long sum = 0;
            for (int i = start; i <= end; i++) {
                sum += array[i];
            }
            return sum;
        } else {
            // Split the array into two halves
            int mid = start + (end - start) / 2;
            ArraySumCalculator leftTask = new ArraySumCalculator(array, start, mid);
            ArraySumCalculator rightTask = new ArraySumCalculator(array, mid + 1, end);

            // Fork the tasks to execute concurrently
            leftTask.fork();
            long rightResult = rightTask.compute(); // Compute the right subarray sum synchronously
            long leftResult = leftTask.join(); // Wait for the left subarray sum

            // Combine the results
            return leftResult + rightResult;
        }
    }

    public static void main(String[] args) {
        int[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

        ArraySumCalculator calculator = new ArraySumCalculator(array, 0, array.length - 1);
        long result = calculator.compute();
        System.out.println("Sum of elements: " + result);
    }
}