Bad Thread Example

Main.java

package org.example;

public class Main {

    public static long result = 0;
    public static void main(String[] args) {
        final int NUM_THREADS = 10;
        final long START_NUM = 0;
        //final long END_NUM = 300000000;
        final long END_NUM = 10000000;
        final long STEP = (END_NUM - START_NUM) / NUM_THREADS;
        Thread[] threads = new Thread[NUM_THREADS];

        for (int i = 0; i < threads.length; i++) {
            long start = i * STEP + 1;
            long end = (i + 1) * STEP;
            threads[i] = new Thread(new MyRunnable(start, end));
            threads[i].start();
        }

            for (int i = 0; i < threads.length; i++) {
                try {
                    threads[i].join();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }

        System.out.println("Result: " + Main.result);
         System.out.println("Program ended...");
    }
}

MyRunnable.java

package org.example;

public class MyRunnable implements Runnable {

    public long s;
    public long e;
    public MyRunnable(Long s, Long e) {
        this.s = s;
        this.e = e;
    }

    public synchronized void someMethod() {
        System.out.println(s + " " + e);
        for (long i = s; i <= e; i++) {
            Main.result += i;
        }
        System.out.println("Thread " + Thread.currentThread().getName() + " finished.");    }

    @Override
    public void run() {
        someMethod();
    }
}