Behavior of concat(null)

[elena votchennikova]

Hello,

I'm trying to use method concat(Stream) of some Stream implementation 
with null-argument and currently it doesn't throw NullPointerException. 
Exception is thrown only when I call some method of the resulting 
Stream, for example iterator().

Could you please explain - is it an expected behavior or concat() with 
null-argument should throw NPE?


Thanks a lot,
Elena