Behavior of allMatch, anyMatch and noneMatch for empty Stream

[Olexandr Demura]

By some unknown reason I percept null to be effectively equal to any chosen
SAM with method defined to throw NPE.
e.g. Streams.emptyStream().anyMatch(o -> ((Boolean) null).booleanValue())

2012/12/12 Vitaly Davidovich <vitalyd at gmail.com>

> Brian,
>
> I think NPE should be thrown when predicate is null irrespective of stream
> length for consistency sake.
>
> Thanks
>
> Sent from my phone
> On Dec 12, 2012 9:16 AM, "Brian Goetz" <brian.goetz at oracle.com> wrote:
>
> > These values are correct.
> >
> > All/None match correspond to universal quantification, which can be
> > vacuously satisfied; Any match corresponds to existential
> > quantification, which cannot.
> >
> > On 12/12/2012 6:26 AM, elena votchennikova wrote:
> > > Hi,
> > >
> > > please clarify behavior of allMatch(Predicate), anyMatch(Predicate) and
> > > noneMatch(Predicate) methods for empty Stream.
> > >
> > > 1) Please look at the next code:
> > > System.out.println(Streams.emptyStream().allMatch(o -> true));
> > > System.out.println(Streams.emptyStream().anyMatch(o -> true));
> > > System.out.println(Streams.emptyStream().noneMatch(o -> true));
> > >
> > > The result output will be:
> > > true
> > > false
> > > true
> > >
> > >
> > > Is it OK? And will such behavior be specified?
> > >
> > > 2) Methods allMatch, anyMatch and noneMatch throw NullPointerException
> > > if Predicate is null, for example:
> > > Stream notEmptyStream = Arrays.stream(new Object[] {new Object()});
> > > notEmptyStream.allMatch(null);
> > >
> > > But if Stream is empty methods will not throw NPE.
> > > So, next code will print same result as in point 1)
> > > System.out.println(Streams.emptyStream().allMatch(null));
> > > System.out.println(Streams.emptyStream().anyMatch(null));
> > > System.out.println(Streams.emptyStream().noneMatch(null));
> > >
>  > > Is it OK or calling these methods with null-Predicate should throws
> NPE?
>