On 6 May 2014 19:19, Paul Benedict <pbened...@apache.org> wrote: > NPE is implicit if the method does not allow an argument to be null. This > doesn't have to be the case. This has nothing to do with the JDK vs. 3rd > party source. It's just about the contract. As long as you document which > arguments can be null, then you're good -- otherwise throw an NPE to > capture the contract violation. > > > Cheers, > Paul
I'm strongly in favour of IAE for incorrect null inputs. It makes it completely clear that the input was validated and found to be lacking. A NPE tends to make me think something unanticipated has happened. I agree with Sebb: NPEs will have people blaming the library before their own code. Duncan > > > On Tue, May 6, 2014 at 12:09 PM, sebb <seb...@gmail.com> wrote: > >> On 6 May 2014 14:27, Benedikt Ritter <brit...@apache.org> wrote: >> > Hi Thiago, >> > >> > >> > 2014-05-06 14:53 GMT+02:00 Thiago Andrade <thia...@gmail.com>: >> > >> >> Hello people, >> >> >> >> Analizing the JIRA issue >> https://issues.apache.org/jira/browse/LANG-1008the >> >> contributors noticed that NumberUtils.max/min methods all have the same >> >> problem: >> >> They all throw an IllegalArgumentException when according to the >> official >> >> documentation (Oracle|Sun) says that a NullPointerException must be >> thrown >> >> when an argument must not be null. >> >> >> > >> > This is not a problem imho. It is a question of API design. >> >> +1 >> >> > I don't now an >> > offical documentation that say when IAE or NPE _must_ be thrown. >> Sun/Oracle >> > at some point decided to throw NPE when ever a null reference is passed >> to >> > a method that doesn't accept null inputs. I don't feel this is right, >> since >> > a null input is also an illegal argument. Why make a differenciation? >> IMHO >> > NPE should be reserved to the JVM, when a method is called on a null >> > reference, but that's just my opinion. >> > >> >> +1. >> >> NPE used to mean a bug had occurred rather than the user had provided bad >> input. >> >> Using NPE for a parameter that must not be null confuses things. >> >> > >> >> >> >> However according to Apache Commons Lang Developer Guide, these methods >> are >> >> all correct. This guide says that "When throwing an exception to >> indicate a >> >> bad argument, always try to throw IllegalArgumentException, even if the >> >> argument was null. Do not throw NullPointerException.". >> >> >> > >> > Since [lang] is currently designed this way, I'd rather deal with this >> > issue for 4.0. We can then revisit our initial decision to only throw IAE >> > an maybe align it to what the JDK now does. If you want to file an issue, >> > my opinion is, that it should be fix version 4.0. Changing the exceptions >> > that are thrown now may break clients (although I think there are very >> few >> > use cases where one should catch IAE or NPE). >> >> If Commons ever decide to switch to NPE (I hope not) then it is >> imperative that the message is 100% clear that the problem is with a >> method argument, and which argument is at fault. >> >> Otherwise we will likely find ourselves fielding bug reports about >> Commons code when it is the caller that is at fault. >> Even then, I suspect some reporters will just see the NPE and assume >> that the Commons code has a bug. >> >> If an argument is invalid, throw IAE. >> IMO it does not make sense to throw NPE for some invalid arguments and >> not others. >> What Sun/Oracle perhaps should have done was introduce an >> "InvalidNullArgumentException" >> >> The Javadoc (1.7) says: >> >> >>> >> Thrown when an application attempts to use null in a case where an >> object is required. These include: >> >> Calling the instance method of a null object. >> Accessing or modifying the field of a null object. >> Taking the length of null as if it were an array. >> Accessing or modifying the slots of null as if it were an array. >> Throwing null as if it were a Throwable value. >> >> Applications should throw instances of this class to indicate other >> illegal uses of the null object. >> <<< >> >> I suppose "illegal use of the null object" could be taken to mean >> passing null to a non-nullable parameter, but I think that is >> stretching it too far. >> >> > >> >> >> >> This mail was sent in order to discuss around and make decisions to >> solve >> >> this dilemma where the Java official specification says X and the Apache >> >> official specification says Y. >> >> >> > >> > Can you please provide a lnk to the official specification you're >> refering >> > to? ;-) >> > >> > Regards, >> > Benedikt >> > >> > >> >> >> >> My sincere thanks for your time and consideration, >> >> >> >> -- >> >> Thiago Andrade >> >> >> > >> > >> > >> > -- >> > 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 >> >> --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
