package runnables;

import java.util.concurrent.atomic.AtomicInteger;

import java.util.concurrent.atomic.AtomicLong;

public class Counter {

public static long count = 0;

// public static AtomicLong count = new AtomicLong();

public static void main(String[] args) throws InterruptedException {

Runnable r = () -> {

for (int i = 0; i < 1_000_000_000L; i++) {

synchronized (Counter.class) {

count++;

}

// count.incrementAndGet();

}

};

System.out.println("count is " + count);

long start = System.nanoTime();

Thread t = new Thread(r);

t.start();

Thread t2 = new Thread(r);

t2.start();

// "happens-before" says "if you look then you will see"..

// join creates a happens-before relationship from the end of the thread (that dies)

// to the continuation of the calling thread

t.join();

t2.join();

long time = System.nanoTime() - start;

System.out.println("count is " + count + ". Time was " + (time / 1_000_000_000.0));

}

}