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"protected" should be obvious, if you've worked on any non-trivial Java codebase. However, I've been working with Java for over 20 years now, and don't think I

"protected" should be obvious, if you've worked on any non-trivial Java codebase. However, I've been working with Java for over 20 years now, and don't think I have ever actually used "volatile" once. The only reason I know anything about it is because I read "Java Concurrency in Practice" once upon a time, and have a really good memory. In my experience with concurrent code in the business world, it's more common to enforce immutability rather than try to manage state updates. On the RARE occasions to the contrary (e.g. a "tripwire" flag of some kind?), accuracy is more important that maximum performance, so you would use an atomic class or something synchronized. Really, I think this example more than anything else just shows that technical interviewing is a speed-dating crapshoot. You just have to interview at enough places to find an opportunity you're excited about, and where you happened to not stumble across any interviewer's personal bugaboos that don't match up with you.

throwaway2037 5y ago
In my career, I have used volatile incorrectly many more times than I have used it correctly. :) For readers who are not deeply familiar with Java's volatile keyword, you can read more about it here: https://stackoverflow.com/questions/13688697/is-a-write-to-a-volatile-a-memory-barrier-in-java https://stackoverflow.com/questions/13688697/is-a-write-to-a... I feel the same about robust, easy to maintain enterprise software: Just use a blocking queue (or disrupter circular buffer for speed freaks) and make all messages/requests immutable. It is a trivial concept to explain to new hires and all but guarantees "boring" thread-safe code can be written by junior devs. I think I finally understood volatile (in a pratical setting) when I read the source code for class CopyOnWriteArrayList. To be honest, the first few times I read it... the pattern made no sense. I thought to myself: "Why use volatile?" After reading many times (and using volatile wrong many times), I finally understood the pattern.

throwaway2037 5y ago

In my career, I have used volatile incorrectly many more times than I have used it correctly. :) For readers who are not deeply familiar with Java's volatile keyword, you can read more about it here: https://stackoverflow.com/questions/13688697/is-a-write-to-a-volatile-a-memory-barrier-in-java https://stackoverflow.com/questions/13688697/is-a-write-to-a... I feel the same about robust, easy to maintain enterprise software: Just use a blocking queue (or disrupter circular buffer for speed freaks) and make all messages/requests immutable. It is a trivial concept to explain to new hires and all but guarantees "boring" thread-safe code can be written by junior devs. I think I finally understood volatile (in a pratical setting) when I read the source code for class CopyOnWriteArrayList. To be honest, the first few times I read it... the pattern made no sense. I thought to myself: "Why use volatile?" After reading many times (and using volatile wrong many times), I finally understood the pattern.