Why are empty catch blocks a bad idea?
I've just seen a question on try-catch, which people (including Jon Skeet) say empty catch blocks are a really bad idea? Why this? Is there no situation where an empty catch is not a wrong design decision?
I mean, for instance, sometimes you want to get some additional info from somewhere (webservice, database) and you really don't care if you'll get this info or not. So you try to get it, and if anything happens, that's ok, I'll just add a "catch (Exception ignored) {}" and that's all
Usually empty try-catch is a bad idea because you are silently swallowing an error condition and then continuing execution. Occasionally this may be the right thing to do, but often it's a sign that a developer saw an exception, didn't know what to do about it, and so used an empty catch to silence the problem.
It's the programming equivalent of putting black tape over an engine warning light.
I believe that how you deal with exceptions depends on what layer of the software you are working in: Exceptions in the Rainforest.
They're a bad idea in general because it's a truly rare condition where a failure (exceptional condition, more generically) is properly met with NO response whatsoever. On top of that, empty catch blocks are a common tool used by people who use the exception engine for error checking that they should be doing preemptively.
To say that it's always bad is untrue...that's true of very little. There can be circumstances where either you don't care that there was an error or that the presence of the error somehow indicates that you can't do anything about it anyway (for example, when writing a previous error to a text log file and you get an IOException , meaning that you couldn't write out the new error anyway).
I wouldn't stretch things as far as to say that who uses empty catch blocks is a bad programmer and doesn't know what he is doing...
I use empty catch blocks if necessary. Sometimes programmer of library I'm consuming doesn't know what he is doing and throws exceptions even in situations when nobody needs it.
For example, consider some http server library, I couldn't care less if server throws exception because client has disconnected and index.html couldn't be sent.
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