Is the != check thread safe?

Question

I know that compound operations such as i++ are not thread safe as they involve multiple operations.

But is checking the reference with itself a t

Answer 1

Regarding the weird behaviour:

Since the variable a is not marked as volatile, at some point it might value of a might be cached by the thread. Both as of a != a are then the cached version and thus always the same (meaning flag is now always false).