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 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 > >
