REQUEST: better empty catch in better exception handling (original) (raw)

Bruce Chapman brucechapman at paradise.net.nz
Wed Mar 25 02:07:38 PDT 2009

I think a better solution to this problem is to add a new method to Throwable thus

public final void ignore() {}

And then you can explicitly ignore an exception like this

}catch(SomeException ex){ ex.ignore(); }

I would hope that hotspot could inline that quite easily :)

I intend to suggest this for the small API changes process which is coming soon.

Bruce

rssh at gradsoft.com.ua wrote:

Yet one problem with extension handler: rare we need catch exception but do nothibg in catch statement. (i. e. do not log) Example is code like next snipset:

try { something=searchFirst(condition); }catch(NotFoundException ex){ // do nothing. search better } if (something!=null) { try { something=searchSecond(condition); }catch(NotFoundException ex){ // do nothing. search better } } >From other side, we prefer do not have in codebase code with empty exception handling and use special tools to detect empty catch braclets and warn about ones. For now, we use ';' to mark, that this empty catch is really empty catch and not error or unfinished refactoring. I.e.: if (something!=null) { try { something=searchSecond(condition); }catch(NotFoundException ex){ // do nothing. search better ; // ';' tell javachecker do not complain about empty catch. } }

But this is ugly. Of course, is simple use annotation @SuppressWarning("empty-catch") but javac compiler does not warn about empty catch-s. So, question to community: is it possible to extend exception handling proposal by adding optional conventions - warn about empty catch-s - specify rare cases, when empty catch is really needed. ? For example, this can be @EmptyCatch annotation, which mark catch block empty. i.e. try { }catch(@EmptyCatch NotFound | FoundNotAsILike ex ){ } and effective do nothing.

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