How can a Java variable be different from itself?

Question

I am wondering if this question can be solved in Java (I\'m new to the language). This is the code:

class Condition {
    // you can change in the main
    p         


        

Answer 1

Not sure if this is an option but changing x from local variable to a field would allow other thread to change its value between the reading left and right side in if statement.

Here is short demo:

class Test {

    static int x = 0;

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

        Thread t = new Thread(new Change());
        t.setDaemon(true);
        t.start();

        while (true) {
            if (x == x) {
                System.out.println("Ok");
            } else {
                System.out.println("Not ok");
                break;
            }
        }
    }
}

class Change implements Runnable {
    public void run() {
        while (true)
            Test.x++;
    }
}

Output:

⋮
Ok
Ok
Ok
Ok
Ok
Ok
Ok
Ok
Not ok