Comments on: Functional vs “Java” Style

By: Tony Morris

Tony Morris — Sun, 20 Sep 2009 11:22:10 +0000

It is true that Java is not well suited to a functional style, but it does raise the question, just what “style” is it suited to?

It is far more suited to a “functional style” than not, as your code provides anecdotal evidence for (the case generalises).

I wish we, as an industry, did away with this Java nonsense and moved on.

By: Dale

Dale — Thu, 03 Sep 2009 17:21:59 +0000

Best to switch to Scala. People like Joshua Bloch have condemned Java to stagnation.

By: Frank

Frank — Tue, 25 Aug 2009 13:15:12 +0000

It really is just a matter of personal preference and not of better readability. The simple fact that the code contains a lot of class and function definition keywords like new, return, public, boolean plus additional parentheses makes this harder to read IMHO. I am sure that there are useful applications of this but stating that the one is “better” than the other is nothing more than an opinion.

Frank

By: Neal Gafter

Neal Gafter — Tue, 25 Aug 2009 06:08:33 +0000

It looks like Google engineers haven’t reached consensus about a functional style in Java. Josh Bloch http://gafter.blogspot.com/2007/12/what-flavor-of-closures.html?showComment=1197631980000#c8863950537789037629 and Cedric Beust http://beust.com/weblog/archives/000517.html are against the functional style in Java, while the authors of Google Collections http://google-collections.googlecode.com/svn/trunk/javadoc/index.html?com/google/common/collect/Iterables.html promote and support it.

By: cyrille

cyrille — Thu, 20 Aug 2009 18:30:27 +0000

Yes a good post indeed. I already tried to express that recently, after 4 years of doing just that in our team.

You do emphasize what’s important: over time a growing set of functors can be reused and composed together (boolean operations etc) as a plumbing kit. We used Apache Commons Collections Predicate, Closure and Transformer a lot (with Java 1.4) and very quickly all the team loved it, without even knowing for a long time that this was called functional style. And the benefits talked for themselves: much higher reuse, less LOC, no side effect, trivial unit testing, flexibility to configure the application at assembly time…

Whenever I mention functional style everybody immediately speaks about Scala, F# or another sexy language, whereas what’s really important is the style in itself (paradigm), not the syntactic sugar.

By: Jason

Jason — Thu, 20 Aug 2009 16:26:38 +0000

Hi Ricky,

Thanks for the comment, although it sounds like I’ll need to be more controversial next time . I have seen Functional Java which looks interesting. I am somewhat wary of the reimplementation of basic collections — have you found this an issue when working with other Java libraries? I’d have to actually try it before I could pass any meaningful judgement.

I actually do really need to look into the alternatives as Pulse currently uses a home-grown library. It was born before there was a decent alternative (particularly one which made use of generics), but I’m sure we’d be better off switching to something more complete now.

By: Ricky Clarkson

Ricky Clarkson — Thu, 20 Aug 2009 16:01:54 +0000

Excellently said. You might also look at Functional Java. I think this is my first ever non-argumentative blog comment.