It feels to me that this misrepresents the ideas expressed here, or at
least mine ;) I am neither indifferent or favor NPE. I favor IAE, so
does that mean I am nor "most people". If a person make these kinds of
statement, we might as well VOTE or argue-discuss some more...!
Gary
On Sep 1, 2013, at 10:46, Benedikt Ritter <brit...@apache.org> wrote:
> Look's like most people are either indifferent or favor NPE. So, do we
> change this for [CSV]? The important thing is to give users an expressive
> message.
>
> Benedikt
>
>
>
> 2013/8/30 Gary Gregory <garydgreg...@gmail.com>
>
>> Surprisingly, a lot. At work, we have a lot of frameworky/plugin-type of
>> code where we run operations on collections of things and we do not want
>> "expected" errors to torpedo the whole processing flow, so we do catch
>> things like IAE and ISE. We do try to avoid catching Exception if we can
>> help it.
>>
>> Gary
>>
>>
>> On Fri, Aug 30, 2013 at 2:32 PM, Matt Benson <gudnabr...@gmail.com> wrote:
>>
>>> How often do you really want to catch these?
>>>
>>> Matt
>>>
>>>
>>> On Fri, Aug 30, 2013 at 1:20 PM, Gary Gregory <garydgreg...@gmail.com
>>>> wrote:
>>>
>>>> Another perspective to think about is whether you want to write code
>>> like:
>>>>
>>>> try {
>>>> // la-di-da
>>>> } catch (NullPointerException e) {
>>>> // garbage in!
>>>> }
>>>>
>>>> or:
>>>>
>>>> try {
>>>> // doo-wap-doo-wap
>>>> } catch (IllegalArugumentException e) {
>>>> // garbage in!
>>>> }
>>>>
>>>> Catching NPE just smells funny to me.
>>>>
>>>> Gary
>>>>
>>>>
>>>>
>>>> On Fri, Aug 30, 2013 at 1:06 PM, sebb <seb...@gmail.com> wrote:
>>>>
>>>>> The fact that NPE is documented in Bloch is quite important.
>>>>>
>>>>> Whatever we do choose, we should make sure to document all th reasons
>>>>> (pros and cons) somewhere other than just the mailing list!
>>>>>
>>>>> On 30 August 2013 17:30, Matt Benson <gudnabr...@gmail.com> wrote:
>>>>>> The discussion for [lang], none of whose participants have weighed
>> in
>>>>> here,
>>>>>> took place in late 2009 (so perhaps a little longer ago than I
>>> thought)
>>>>> and
>>>>>> is archived at [1]. IMO Paul B. makes some pretty compelling
>>> arguments
>>>>> in
>>>>>> [2].
>>>>>>
>>>>>> Matt
>>>>>>
>>>>>> [1] http://markmail.org/thread/7gw7xzrc3c3ul74c
>>>>>> [2] http://markmail.org/message/wmc4jh4pmhjjtxdf
>>>>>>
>>>>>>
>>>>>> On Fri, Aug 30, 2013 at 11:13 AM, sebb <seb...@gmail.com> wrote:
>>>>>>
>>>>>>> The JDK Javadoc says of NPE:
>>>>>>>
>>>>>>> * Applications should throw instances of this class to indicate
>>>>>>> * other illegal uses of the <code>null</code> object.
>>>>>>>
>>>>>>> and of IAE:
>>>>>>>
>>>>>>> * Thrown to indicate that a method has been passed an illegal or
>>>>>>> * inappropriate argument.
>>>>>>>
>>>>>>> That says to me that we should throw IAE here.
>>>>>>>
>>>>>>> The JDK does use NPE for parameter checks, but it also uses IAE,
>> for
>>>>>>> example:
>>>>>>>
>>>>>>> javax.management.monitor.Monitor.addObservedObject
>>>>>>> java.rmi.activation.ActivationDesc.ActivationDesc
>>>>>>> javax.management.relation.RoleList.add
>>>>>>> javax.imageio.metadata.IIOMetadataFormatImpl.addAttribute
>>>>>>>
>>>>>>> On 30 August 2013 16:50, Adrian Crum <
>>>>> adrian.c...@sandglass-software.com>
>>>>>>> wrote:
>>>>>>>> I've seen a lot of discussions on NPE versus IAE, and in the end
>>>> they
>>>>> all
>>>>>>>> condense down to what Matt stated here: Those who favor NPE cite
>>> the
>>>>> JDK
>>>>>>>> classes as a pattern to follow, and those who favor IAE say it
>> is
>>> a
>>>>>>> better
>>>>>>>> description of the problem. From my perspective, both are valid
>>>>>>> viewpoints,
>>>>>>>> and a project simply needs to choose one. In the end, the choice
>>> is
>>>>>>> neither
>>>>>>>> "right" nor "wrong" - it is just a choice.
>>>>>>>>
>>>>>>>> -Adrian
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 8/30/2013 8:07 AM, Matt Benson wrote:
>>>>>>>>>
>>>>>>>>> Let me stir the pot:
>>>>>>>>> At a fundamental level I agree that a required *argument*
>>> should
>>>>>>> throw
>>>>>>>>> an
>>>>>>>>> IllegalArgumentException when null is supplied. However, ISTR
>>> the
>>>>>>>>> decision
>>>>>>>>> to do otherwise in [lang] having been discussed on-list in the
>>>>>>>>> not-so-distant past, and the result of that discussion being
>> that
>>>>> NPE is
>>>>>>>>> usually the result in the core JDK classes. So I wouldn't
>>>>> characterize
>>>>>>>>> the
>>>>>>>>> situation as "[lang] *just happens* to throw NPE." Now, [lang]
>>> is
>>>>> in a
>>>>>>>>> slightly unique situation as its stated mission is to
>> complement
>>>> Java
>>>>>>> SE,
>>>>>>>>> so it could be argued that [lang] is under greater pressure to
>>>>> conform
>>>>>>> for
>>>>>>>>> that reason. But my personal preference, in light of the
>>> standing
>>>>>>>>> decision
>>>>>>>>> with [lang], would be for consistency throughout Commons
>>> components
>>>>>>>>> *despite* the fact that at a purely semantic level I agree with
>>> the
>>>>>>>>> arguments in favor of IllegalArgumentException.
>>>>>>>>>
>>>>>>>>> To summarize, +1 for NullPointerException from me.
>>>>>>>>>
>>>>>>>>> Matt
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Fri, Aug 30, 2013 at 9:36 AM, Benedikt Ritter <
>>>> brit...@apache.org
>>>>>>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> 2013/8/30 sebb <seb...@gmail.com>
>>>>>>>>>>
>>>>>>>>>>> On 30 August 2013 15:19, Benedikt Ritter <brit...@apache.org
>>>
>>>>> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>> I've removed the generics in r1518974, thanks for spotting
>>> that
>>>>> sebb.
>>>>>>>>>>>>
>>>>>>>>>>>> Regarding the exception to throw I'm indifferent. The
>>> important
>>>>> thing
>>>>>>>>>>
>>>>>>>>>> is
>>>>>>>>>>>
>>>>>>>>>>> to
>>>>>>>>>>>>
>>>>>>>>>>>> fail early.
>>>>>>>>>>> ... and with a helpful message.
>>>>>>>>>>>
>>>>>>>>>>>> I personally thing that NPE should be reserved for signaling
>>>> that
>>>>>>> some
>>>>>>>>>>>
>>>>>>>>>>> code
>>>>>>>>>>>>
>>>>>>>>>>>> tried to invoke a method on a null reference.
>>>>>>>>>>>
>>>>>>>>>>> +1
>>>>>>>>>>>
>>>>>>>>>>>> In our case null is illegal because we know that some code
>>> later
>>>>> on
>>>>>>>>>>
>>>>>>>>>> would
>>>>>>>>>>>>
>>>>>>>>>>>> break if we accept a null reference. So
>> IllegalStateException
>>>>> makes
>>>>>>>>>>>
>>>>>>>>>>> sense.
>>>>>>>>>>>
>>>>>>>>>>> s/IllegalStateException /IllegalArgumentException/
>>>>>>>>>>>
>>>>>>>>>>> +1
>>>>>>>>>> Sorry, I meant IAE of corse.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>>> Imaging having a method that accepts an int and only
>> positive
>>>> ints
>>>>>>> are
>>>>>>>>>>>> valid. You would throw an IllegalArgumentException if a
>>> negative
>>>>> int
>>>>>>> is
>>>>>>>>>>>> passed to that method and not a NegativeIntegerException (or
>>>> what
>>>>>>>>>>
>>>>>>>>>> ever).
>>>>>>>>>>>>
>>>>>>>>>>>> But James has a point. If [LANG] uses NPE maybe we should
>>> stick
>>>> to
>>>>>>>>>>
>>>>>>>>>> this.
>>>>>>>>>>>
>>>>>>>>>>> I don't think we have to do the same as LANG, so long as the
>>>>> Javadoc
>>>>>>> is
>>>>>>>>>>> clear.
>>>>>>>>>>>
>>>>>>>>>>>> Feel free to change it. I'll leave it for now since there
>>>> doesn't
>>>>>>> seem
>>>>>>>>>>
>>>>>>>>>> to
>>>>>>>>>>>>
>>>>>>>>>>>> be consensus?!
>>>>>>>>>>>
>>>>>>>>>>> Unless there are other reasons than "LANG happens to use
>> NPE" I
>>>>> think
>>>>>>>>>>> we should stick with IAE, as it more clearly indicates the
>> the
>>>>> problem
>>>>>>>>>>> is not within the method throwing it.
>>>>>>>>>>>
>>>>>>>>>>> The problem with using NPE to flag parameter errors is that
>> it
>>>>>>>>>>> confuses the user as to the likely cause.
>>>>>>>>>>>
>>>>>>>>>>> Leave NPEs to the runtime system.
>>>>>>>>>> agreed.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>>> Benedikt
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> 2013/8/30 James Carman <ja...@carmanconsulting.com>
>>>>>>>>>>>>
>>>>>>>>>>>>> Well, the problem with using NPE is that we as Java
>>> developers
>>>>> have
>>>>>>>>>>>>> learned through the years that NPE typically is an "oh
>> crap"
>>>>>>>>>>>>> situation, where something is terribly wrong (we hate
>> seeing
>>>>> those).
>>>>>>>>>>>>> Thus, our users may have knee-jerk reactions and not even
>>> know
>>>> to
>>>>>>>>>>>>> inspect the message for the real cause. IAE is less
>>> alarming,
>>>>> IMHO.
>>>>>>>>>>>>> Just my $0.02, but we've been doing it that way for a long
>>> time
>>>>> in
>>>>>>>>>>>>> [lang], so be it.
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Fri, Aug 30, 2013 at 9:01 AM, sebb <seb...@gmail.com>
>>>> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> AFAIK "accidental" NPEs don't have a message associated
>> with
>>>>> them.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> So provided that the assertion generates the NPE with a
>>>> suitable
>>>>>>>>>>>>>> message (e.g.as currently done for the IAE) then it
>>> *should*
>>>> be
>>>>>>>>>>>>>> possible for the end user to distinguish the two cases.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I am slightly in favour of retaining IAE as the cause is
>>>> obvious
>>>>>>>>>>
>>>>>>>>>> with
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> needing to look at the NPE message.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> ==
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Horrible hack: - if you want to use NPE, you could wrap an
>>> IAE
>>>>> in
>>>>>>>>>>
>>>>>>>>>> the
>>>>>>>>>>>>>
>>>>>>>>>>>>> NPE:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> npe = new NPE(msg);
>>>>>>>>>>>>>> npe.initCause(new IAE(msg));
>>>>>>>>>>>>>> throw npe;
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Or vice-vera, of course!
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Not sure that gains anything, but it does make the stack
>>> trace
>>>>> look
>>>>>>>>>>>>>> more impressive!
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On 30 August 2013 13:42, James Carman <
>>>>> ja...@carmanconsulting.com>
>>>>>>>>>>>>>
>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Commons Lang's Validate.notNull() throws NPEs. I don't
>>> know
>>>>> that
>>>>>>>>>>>
>>>>>>>>>>> I've
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> necessarily agreed with that, but at some point a
>> decision
>>>> was
>>>>>>> made
>>>>>>>>>>>>>>> that null constraint violations should throw NPEs. Food
>>> for
>>>>>>>>>>
>>>>>>>>>> thought.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> On Fri, Aug 30, 2013 at 8:32 AM, Gary Gregory <
>>>>>>>>>>>
>>>>>>>>>>> garydgreg...@gmail.com>
>>>>>>>>>>>>>
>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> On Fri, Aug 30, 2013 at 8:25 AM, Emmanuel Bourg <
>>>>>>>>>>
>>>>>>>>>> ebo...@apache.org>
>>>>>>>>>>>>>
>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> + if (parameter == null) {
>>>>>>>>>>>>>>>>>>> + throw new
>>>> IllegalArgumentException("Parameter
>>>>> '"
>>>>>>>>>>
>>>>>>>>>> +
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> parameterName + "' must not be null!");
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> + }
>>>>>>>>>>>>>>>>>>> + }
>>>>>>>>>>>>>>>>>>> +}
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Isn't a null value supposed to throw a NPE ?
>>>>>>>>>>>>>>>> Not always IMO. When I see an NPE I assume something is
>>> very
>>>>>>> wrong
>>>>>>>>>>>
>>>>>>>>>>> and
>>>>>>>>>>>>>
>>>>>>>>>>>>> that
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> it could be a bug in the impl OR a call site, somewhere
>> on
>>>> the
>>>>>>>>>>
>>>>>>>>>> code
>>>>>>>>>>>>>
>>>>>>>>>>>>> path.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> With an IAE, I know for sure it's a problem in the call
>>> site
>>>>>>>>>>
>>>>>>>>>> (which
>>>>>>>>>>>>>
>>>>>>>>>>>>> could
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> be a bug of course).
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I does not help that the JRE/JDK is inconsistent, so
>> it's
>>>>> hard to
>>>>>>>>>>>
>>>>>>>>>>> find
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> examples.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Gary
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Emmanuel Bourg
>>>>> ---------------------------------------------------------------------
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> To unsubscribe, e-mail:
>>> dev-unsubscr...@commons.apache.org
>>>>>>>>>>>>>>>>> For additional commands, e-mail:
>>>> dev-h...@commons.apache.org
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>>> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org
>>>>>>>>>>>>>>>> Java Persistence with Hibernate, Second Edition<
>>>>>>>>>>>>>
>>>>>>>>>>>>> http://www.manning.com/bauer3/>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> JUnit in Action, Second Edition <
>>>>>>> http://www.manning.com/tahchiev/
>>>>>>>>>>>>>>>> Spring Batch in Action <
>> http://www.manning.com/templier/>
>>>>>>>>>>>>>>>> Blog: http://garygregory.wordpress.com
>>>>>>>>>>>>>>>> Home: http://garygregory.com/
>>>>>>>>>>>>>>>> Tweet! http://twitter.com/GaryGregory
>>>>> ---------------------------------------------------------------------
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> To unsubscribe, e-mail:
>> dev-unsubscr...@commons.apache.org
>>>>>>>>>>>>>>> For additional commands, e-mail:
>>> dev-h...@commons.apache.org
>>>>> ---------------------------------------------------------------------
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> To unsubscribe, e-mail:
>> dev-unsubscr...@commons.apache.org
>>>>>>>>>>>>>> For additional commands, e-mail:
>>> dev-h...@commons.apache.org
>>> ---------------------------------------------------------------------
>>>>>>>>>>>>> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
>>>>>>>>>>>>> For additional commands, e-mail:
>> dev-h...@commons.apache.org
>>>>>>>>>>>>
>>>>>>>>>>>> --
>>>>>>>>>>>> http://people.apache.org/~britter/
>>>>>>>>>>>> http://www.systemoutprintln.de/
>>>>>>>>>>>> http://twitter.com/BenediktRitter
>>>>>>>>>>>> http://github.com/britter
>>>>> ---------------------------------------------------------------------
>>>>>>>>>>> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
>>>>>>>>>>> For additional commands, e-mail: dev-h...@commons.apache.org
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> http://people.apache.org/~britter/
>>>>>>>>>> http://www.systemoutprintln.de/
>>>>>>>>>> http://twitter.com/BenediktRitter
>>>>>>>>>> http://github.com/britter
>>>> ---------------------------------------------------------------------
>>>>>>>> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
>>>>>>>> For additional commands, e-mail: dev-h...@commons.apache.org
>>> ---------------------------------------------------------------------
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>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
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>>>>
>>>>
>>>> --
>>>> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org
>>>> Java Persistence with Hibernate, Second Edition<
>>>> http://www.manning.com/bauer3/>
>>>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/>
>>>> Spring Batch in Action <http://www.manning.com/templier/>
>>>> Blog: http://garygregory.wordpress.com
>>>> Home: http://garygregory.com/
>>>> Tweet! http://twitter.com/GaryGregory
>>
>>
>>
>> --
>> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org
>> Java Persistence with Hibernate, Second Edition<
>> http://www.manning.com/bauer3/>
>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/>
>> Spring Batch in Action <http://www.manning.com/templier/>
>> Blog: http://garygregory.wordpress.com
>> Home: http://garygregory.com/
>> Tweet! http://twitter.com/GaryGregory
>
>
>
> --
> http://people.apache.org/~britter/
> http://www.systemoutprintln.de/
> http://twitter.com/BenediktRitter
> http://github.com/britter
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