[ajuc]

I agree in general case, but this example

     transactions.stream()
                 .filter(t -> t.getType() == Transaction.GROCERY)
                 .sorted(comparing(Transaction::getValue).reversed())
                 .map(Transaction::getId)
                 .collect(toList());

seems to be net improvement to me. It reads like SQL, and eliminates many causes of error (wrong indexing variables, off-by-one, copy-paste error in boilerplate).

Yes it requires learning several new concepts, but in the end it pays off.

BTW I wouldn't switch old code to this style, because there never seems to be time for that. But new code written like that is perfectly OK IMHO.

EDIT: I really should've checked the code more carefully - the initial version had no indexing variables. Still, it reads better and has less boilerplate.

[andrewprock]

While some people may like to read code that looks like SQL, I've found Java 8 features like this are poorly supported by the debugger, so debugging stuff like this tends to require "horse whispering" or rewriting the logic into something that can be stepped through.

[amirouche]

GNU Gremlin is a stream API to traverse graphs.

[eru]

That reads more like Haskell than like SQL. (Doesn't have any bearing on the rest of your point one way or another.)

[amirouche]

I think it reads better with intermediary variables. Granted sometime you go to name an intermediary variable that does two things (just like male_siblings = (2 * (X + Y)) if I have a brillant idea for the variable name.