 When an individual thread executes, it will appear as if all of the actions taken by that thread occur in the order they appear in the program, even if the actions themselves occur out of order.If one thread executes its instructions out of order, then another thread might see the fact that those instructions were executed out of order, even if that did not affect the semantics of the first thread.For example, consider two threads with the following instructions, executing concurrently, where the variables x and y are both initialized to 0