Ask HN: Shouldn't a recent CS grad know how to throw an exception?

Granted, I know how to throw an exception, but the large majority of my undergrad career was about solving problems that were evaluated on 'well-formed' data. It was rare for the code to need to be able to handle exceptions. Perhaps this is the culprit.

My CS program focused strongly on OO and our core language was Java. Exceptions were a regular subject and part of assignments. It seems insane that someone could have a CS degree and not know something so simple and fundamental.

Most of my CS assignments did something like this:

try { doSomethingBad(); } catch(Exception e){ }

Rarely did we have to think about throwing exceptions, just capturing them.

I can honestly say that in my course work I can't remember ever having to throw an exception. With that being said, I would think anyone who has done any work outside of course work should at least know how to throw an exception.

I know I did.

Exceptions are not "thrown" but caused, raised at best... The way Exceptions are provided in Java are bad if you'd ask me. Anyway you should expect CS graduates with experience in Python, Ruby, C++, Java, ML, Haskell or similar languages to be able to handle exceptions. Anyway. The question remains why you even want a CS graduate to do Java? Also there are slight differences in the semantics of exceptions in aforementioned languages though i.e. C++ Exceptions are "thrown" without operator new but is syntactically quite similar.

So. Do you think throwing exceptions is a must have for entry-level Java development? I don't. It is not important during most simple projects (which you'd do in your curriculum), is most often ignored or rethrown, or looked up and understood in a few minutes. Aren't patterns more important? Or general ideas? Java is just another language which will become a burden (Luke COBOL). Just my thoughts...

Your expectations are really that unreasonable... if you're hiring CS grads without work experience. CS degree programs are not Java developer training, and it's unlikely any kind of classwork would require throwing an exception in any language; catching one maybe. For my own anecdoctal CS program experience, I wrote more functional code than OO, and was never required to use Java in any course.

You're expecting specific professional experience from people that don't have any. Exception handling is not an academic topic. It doesn't help students learn about data structures, algorithms, language development, compiler theory, etc... it's just a control flow construct used by some languages and not others. It's something they'll learn on the job if their job requires it -- easily enough, I'm sure.

If you want that specific knowledge, then require a year of work experience with Java in the job listing. Graduates don't have that by default.

If it's stated that the position is a Java position, then you would reasonably expect the people applying to know how to throw an exception. Computer science has nothing to do with it.

Seems reasonable, assuming you asked about Java experience and they say they're familiar with the language.

A related question has been bugging me recently: why is there such a mismatch between the expectations of employers and the skills of CS graduates? There turns out to be a lot of research from the ACM SIGCSE (Computer Science Education) community. The McCracken Group paper "A multi-national, multi-institutional study of assessment of programming skills of first-year CS students" and several follow-on studies suggest that getting students to learn programming is truly difficult, a universal observation not just limited to the US. Student performance are often bimodal in intro classes. Also, our conventional assessment tools do not measure programming skill very well. I haven't encountered any data on this, but anecdotally, it seems the expectation gap is considerably different from say the expectation-skill gap in electrical and mechanical engineers. If anyone has any perspective on this, I am really interested in hearing about it.

Aside: At least in some (advanced?) compiler courses, we do teach students how to implement exception handling semantics in a compiler. This is of course very different from learning how to use exception handling facilities in a given language.

A CS program would not necessarily teach that. Some schools which use Java as an intro language might have one lecture on exceptions. Otherwise it might be covered in a "Software Engineering" elective.

The list of things a new graduate won't know is endless. What matters is what they do know, and even more what they do when they don't know.

I think, "What do you know about exceptions?" is the sort of question which can indicate both. Probably makes for a more interesting interview as well.

It would be a good idea to make the phone screen more rigorous. Use some etherpad clone-du-jour and have them write code in the phone screen. This way you'll filter out the bozos more efficiently.

You shouldn't expect somebody hired for an entry-level Java position to even know Java. I mean, at least if you're trying to hire somebody who'd be good, they'll have experience in other languages, and the cost of them catching up on Java is miniscule compared to the cost of them catching up with your codebase, with being a professional programmer in general, and it's certainly less than the cost of searching for somebody who's not quite as smart and talented but has better Java-specific knowledge. If you find somebody who has weak knowledge in _everything_, they might still be okay, but if you find somebody who has fairly good knowledge of other aspects of programming (be it another language, or data structures, or HTML or web programming or some protocols and such) then it's a sign that they're not dumb and are worth considering. You should be comfortable simulating how quickly they'd pick up Java when starting.

Edit: Of course, there _are_ a lot of fresh graduates who are scrubs that can't code, signed up for the video games or the money, and thought they'd just focus on grades and they just suck in general. People with general Java background knowledge who just don't know that Java has exceptions are one thing, people who mess up the exception-throwing syntax or forget about checked exceptions are another. What kind of person are they -- did they go to film school or did they go to "films"? People who went to film school will know what their professors told them to know, people who went to films might not have looked at Java specifically but will have a bunch of other knowledge about programming that they looked at outside of class.

Having just graduated from a UK degree in CS i can im not surprised some people cannot do simple tasks like that. University doesn't really prepare you for a certain language or skill, its up to the individual to take that bit of knowledge and apply it further - (in there own time)

Personally i gained more in my own time / placement however university gave me the tools and direction.

I would recommend finding grads that have completed time in industry, the difference between those that did and those that didnt shocked even myself on returning for my final year.

I *would expect to grad to be able to throw and exception and catch them tbh.

I got a java job out of college and would have (and still probably) would fail your test. I can't remember the last time I used an exception in Java

I'd say it depends. If they consider Java to be their primary language and they haven't spent enough time coding in it to have ever encountered exceptions, then they haven't spent enough time coding, period (I'm assuming exceptions weren't the only gap in their knowledge, and this was just an example?). If they consider something else to be their primary language, and are otherwise solid on their CS fundamentals, then by all means, cut them some slack.