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Comment by stinos | Hacker News Reader

Not just Java. I've seen similar classes in C++ and C# to indicate things which should never occur/are clearly bad programmer mistakes/... Think InternalErrorException/DevFailedError etc. Sometimes it's just a sane thing to do, and using such names means you don't need to write the dreaded 'should never happen' comment manually anymore.

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To elaborate a bit, in C++ the relevant exception class is called `std::logic_error` (contrast with `std::runtime_error`). I like it. It is a bit more descriptive of the actual situation than "this should never happen".

In C#, I tend to use the built-in InvalidOperationException class -

https://msdn.microsoft.com/en-us/library/system.invalidopera...

Isn't that what assertions are for?

Assertions can be disabled at runtime. If your goal is to call out the fact that something has gone fundamentally wrong with your program's state, an exception is the way to go.

in Python, running with `-O`, from .pyo files, or equivalent settings in your webserver will all disable assertions. surprise!

I don't think it is a programmer error. Many times when you program against some less reliable API or doing some network stuff the variety of exceptional situations can be really overwhelming. Such exceptions can be some sort of sink to evaluate later whether you still need to improve the code to handle some very specific corner cases.

Right. The best ones are the ones that tell not only that something is wrong, but explicitly says what should be fixed.

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