Code Snippet on Java Concurrency

concurrency.java

/*
Using the synchronized keyword to protect blocks of code within a method.
This block is guarded by a key, which can be either a string or an object
This key is called the lock
*/


public synchronized void critial() {
    // some thread critical stuff
}

public class MyRunnable implements Runnable {
    private final long count;
    
    MyRunnable(long count) {
        this.count = count;
    }
    
    @Override
    public void run() {
        long sum = 0;
        for (long i = 1; i < count; i++) {
            sum += 1;
        }
        System.out.println(sum);
    }
}

public class MyCallable implements Callable<Long> {
    @Override
    public Long call() throws Exception {
        long sum = 0;
        for (long i = 0; i <= 100; i++) {
            sum += i;
        }
        return sum;
    }
}