[mumblemumble]

Is there anything special about singletons here?

In Java, there's no real difference between a singleton and any other object. A singleton is an object that just happens to have a single instance. Practically speaking, they're typically used as a clever design pattern to "work around" Java's lack of language-level support for global variables, so there's that. But I think that that fact might not be relevant to the issue at hand?

The more basic issue is, if you have two different threads concurrently executing `myFunction`, what happens when they're both operating on the same instance of `FooObject`?

[dragontamer]

> Is there anything special about singletons here?

No, aside from the fact that the root commenter clearly understands the issue with global variables, but not necessarily singletons.

I'm trying to use the singleton concept as a "teaching bridge" moment, as the Singleton is clearly "like a global variable" in terms of the data-race, but generalizes to any object in your code.

The commenter I'm replying seems to think that global-variables are the only kind of variable where this problem occurs. He's wrong. All objects and all variables have this problem.