I had a question related to accessing individual elements via an Atomic Reference. If I have an IntegerArray and an atomic reference to it;will reading and writing to individual elements of the array via the AtomicReference variable cause data races?
In the code below: num is an Integer Array with aRnumbers being the atomic reference to the array. In threads 1 and 2; I access aRnumbers.get()[1] and increment it by 1.
I am able to access individual elements via the atomic reference without data races to accurate results each time with 22 as the output of aRnumbers.get()[1] in the main thread after both threads complete.
But,since the atomic reference is defined on the array and not on the individual elements; shouldn't there be a data race in this case leading to 21/22 as the output?
Isn't having data races in this case the motivation for having a AtomicIntegerArray data structure which provides a separate AtomicReference to each element?
Please find below the java code that i am trying to run.Could anyone kindly let me know where I am going wrong.
import java.util.concurrent.atomic.AtomicReference;
public class AtomicReferenceExample {
private static int[] num= new int[2];
private static AtomicReference<int[]> aRnumbers;
public static void main(String[] args) throws InterruptedException {
Thread t1 = new Thread(new MyRun1());
Thread t2 = new Thread(new MyRun2());
num[0]=10;
num[1]=20;
aRnumbers = new AtomicReference<int[]>(num);
System.out.println("In Main before:"+aRnumbers.get()[0]+aRnumbers.get()[1]);
t1.start();
t2.start();
t1.join();
t2.join();
System.out.println("In Main after:"+aRnumbers.get()[0]+aRnumbers.get()[1]);
}
static class MyRun1 implements Runnable {
public void run() {
System.out.println("In T1 before:"+aRnumbers.get()[1]);
aRnumbers.get()[1]=aRnumbers.get()[1]+1;
}
}
static class MyRun2 implements Runnable {
public void run() {
System.out.println("In T2 before:"+aRnumbers.get()[1]);
aRnumbers.get()[1]=aRnumbers.get()[1]+1;
}
}
}
