SumTask.java

package basic;

public class SumTask {
    

    private long startRange, endRange;
    private long sum;
    private static final long RANGE = Integer.MAX_VALUE;

    public SumTask(long startRange, long endRange) {
        this.startRange = startRange;
        this.endRange = endRange;
    }

    public long getSum() {

        for(long i = startRange; i <= endRange; i++) {
            sum += i;
        }
        return sum;
    }


    static public void singleThreadSum() {
        System.out.println("Single thread sum starting..");
        long start = System.currentTimeMillis();
        SumTask sumTask = new SumTask(1, RANGE);
        sumTask.getSum();

        long end = System.currentTimeMillis();
        System.out.println("Single thread sum took " + (end - start) + " ms");
    }

    static public void multiThreadSum() {
        System.out.println("Multi thread sum starting..");
        long start = System.currentTimeMillis();
        SumTask sumTask1 = new SumTask(1, RANGE / 2);
        SumTask sumTask2 = new SumTask(RANGE / 2 + 1, RANGE);
        Thread thread1 = new Thread(sumTask1::getSum);
        Thread thread2 = new Thread(new Runnable() {
            @Override
            public void run() {
                sumTask2.getSum();
            }
        });

        thread1.start();
        thread2.start();

        try {
            thread1.join();
            thread2.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        long end = System.currentTimeMillis();
        System.out.println("Multi thread sum took " + (end - start) + " ms");
    }

    public static void main(String[] args) {
        singleThreadSum();
        multiThreadSum();
    }

}