atomic

import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.concurrent.locks.*;

class test implements Runnable {
        AtomicLong al = new AtomicLong(0);
        final long n = 40000000l;

        public void run() {
                for(long i=0; i<n; i++)
                        al.incrementAndGet();
        }

        public static void main(String [] args) throws Exception {
                test inst = new test();
                inst.run(); // warm-up

                long start = System.nanoTime();
                inst.run();
                inst.run();
                long end1 = System.nanoTime() - start;
                System.out.println("" + end1 / (double)inst.n);

                Thread t1 = new Thread(inst);
                Thread t2 = new Thread(inst);
                start = System.nanoTime();
                t1.start();
                t2.start();
                t1.join();
                t2.join();
                long end2 = System.nanoTime() - start;
                System.out.println("" + end2 / (double)inst.n);
        }
}