Sorting streams containing nulls

[Howard Lovatt]

The expert groups has decided to go with allowing nulls and using an Option type and as a result if you don't filter out nulls [.filter(x->x!=null)] then you will get NPE. My preference would be for nulls to be banned, like ConcurrentHashMap does. But it is hardly the end of the world, just annoying that you have to put filters in if in doubt. 

Sent from my iPad

On 13/11/2012, at 4:08 PM, Georgiy Rakov <georgiy.rakov at oracle.com> wrote:

> On 07.11.2012 18:08, Sergey Kuksenko wrote:
>> But it is sorted stream.
>> How should we compare null with other values?
> The supplied comparator could treat nulls in a special way. There are 
> some ways to do it for instance:
> - comparator could consider null as the lowest value;
> - when sorting integers comparator could consider null being equal to 
> some integer value for instance 5;
> 
> Georgiy
> 
>> 
>> On 11/07/2012 05:43 PM, Remi Forax wrote:
>>> On 11/07/2012 02:30 PM, Brian Goetz wrote:
>>>> The exact specification is not yet written, but we are not expecting stream implementations or operations to do anything special with nulls.  This means nulls may be passed to lambdas or inserted into collections that do not support them, resulting in NPE.
>>> so it's an implementation bug ?
>>> All Queue don't accept null so either null need to be masked/unmasked or
>>> the implementation has to be changed.
>>> 
>>> Rémi
>>> 
>>>> 
>>>> 
>>>> On Nov 7, 2012, at 5:22 AM, Georgiy Rakov wrote:
>>>> 
>>>>> Hello.
>>>>> 
>>>>> When we make sorted(...).iterator() on Stream instance containing one
>>>>> ore more nulls we receive NPE. The example of stack trace is below:
>>>>> 
>>>>>      java.lang.NullPointerException
>>>>>           at java.util.PriorityQueue.offer(PriorityQueue.java:320)
>>>>>           at java.util.PriorityQueue.add(PriorityQueue.java:306)
>>>>>           at java.util.streams.ops.SortedOp.iterator(SortedOp.java:105)
>>>>>           at java.util.streams.ops.SortedOp.wrapIterator(SortedOp.java:97)
>>>>>           at
>>>>>      java.util.streams.AbstractPipeline.iterator(AbstractPipeline.java:329)
>>>>>           ...
>>>>> 
>>>>> Could you please tell if it is considered as expected behavior or it's
>>>>> going to be fixed somehow.
>>>>> 
>>>>> Georgiy.
>>>>> 
>>> 
>> 
>