CompletableFuture.supplyAsync(() -> otherService.get())
                .thenAccept(value -> {
                    // do something
                });

Is there a infinite loop behind it to check the status?
I read some documentation and the answer is “callback”. But when is the “callback” called?

I have researched a lot of documents but have not found the answer yet. Can someone help me explain this issue. Thanks a lot