Why is Thread detecting two objects even though one was created?

public class ThreadExample {

    public static ArrayList<ThreadExample> instances = new ArrayList<ThreadExample>();

    public ThreadExample() {
        instances.add(this);
    }

    public static void main(String[] args) {
        ThreadRead threadRead = new ThreadRead();
        ThreadCreate threadCreate = new ThreadCreate();
        threadCreate.start();
        threadRead.start();

    }

}

class ThreadRead extends Thread {
    public void run() {
        System.out.println(ThreadExample.instances.size());
    }
}

class ThreadCreate extends Thread {
    public void run() {
        ThreadExample.instances.add(new ThreadExample());
    }
}

The output of the code is "2"

The output I expected from the code was 1 or 0. Because if ThreadCreate reads ThreadRead at the same time while creating an object, I could expect "0" to come up because it will read before the construction of the object is completed. Or everything would go well and I would get the result "1". What is going on here that I don’t know?

Thanks.

>Solution :

Because you added twice.
You add a object.

ThreadExample.instances.add(new ThreadExample());

And you add again

instances.add(this);