I use the term “useless” relatively. Let me try to explain. A grocery store that sells 1L milk for $20 is completely useless to milk consumers, all other things equal, than another grocery store that sells 1L milk for $2. It’s simply universally poor economy. There is no exception to this rule and the same is true for Java for solving software problems (not to be confused with other goals for which Java may be suitable).

Unfortunately critics of the claim barely understand Java, let alone the deeper topics of why it might be useless so I am somewhat resigned to ever hearing a reasonable counter-argument and no longer expend effort on the pursuit of the (non?)-existence of such a thing.

I hope this explanation helps clarify the point (and so address your latter question in context). I’m happy to hear that Functional Java helps you.

If that’s the case Tony, why are you wasting your precious time writing useless, impractical library called Functional Java?
I’m finding it hard to reconcile your words with your actions.
Could you care to explain?
By the way, I have used your excellent library in 2 production applications and I find it useful though its written in java.
Is it possible to have a useful library written in useless language?

I do, however, contend that software problems are not being solved, since Java is so utterly useless for such an objective, to the extent of being impossible.

It is unfortunate for you and I this “developed market” is in contention with “solving problems”, despite all the illusions that masquerade no such contention.

and with an apology for a 2-year old response, but aren’t we running into a simple definition-of-terms problem? “Useful” as people mean it about Java is closer to “simple enough that it can be widely understood to some functional degree, and a large enough market can develop that a lot of people can get paid to do it”. Its properties as one of the many programming languages in the Universe are irrelevant.

Perhaps I should have clarified that point.

Here is a more robust implementation of the optional type using Java

The names have changed slightly (to reflect ML-style):

• Maybe -> Option
• Just -> Some
• Nothing -> None

“Therefore, the Maybe data type has 2 and only 2 constructors. It is the “and only 2″ that makes this data type a closed algebraic data type.”

but further down, you say the equivalent is to only allow two subclasses of that type.

Two constructors and two subclasses are very different thing, which is it?

Here is a post that talks about that link:
http://blog.tmorris.net/algebraic-data-types-again/

Nate, don’t give up! Haskell is a deeply beautiful language and learning it will make you a better programmer even if Perl remains your day job! It will make you rethink what a program is and what programming is about.

Don’t let this the too stereotypical conception of functional programmers as played by “Runar” and “Tony” scare you away! Go watch some videos of Simon Peyton Jones and Phillip Wadler. They’re f***ing geniuses who manage to say why they think there are better alternatives to today’s languages without resorting to whining about “cults” or saying that mainstream languages are “useless.” In fact, SPJ jokingly called early attempts at purely functional languages “safe but useless” while traditional imperative languages were “unsafe but useful” http://channel9.msdn.com/showpost.aspx?postid=326762. It’s pure self deprecating humor. Haskell is useful. See Darcs as a very practical example of what Haskell can do.

Don’t let this the too stereotypical conception of functional programmers as played by “Runar” and “Tony” scare you away! Go watch some videos of Simon Peyton Jones and Phillip Wadler. They’re fucking geniuses who manage to say why they think there are better alternatives to today’s languages without resorting to whining about “cults” or saying that mainstream languages are “useless.” In fact, SPJ jokingly called early attempts at purely functional languages “safe but useless” while traditional imperative languages were “unsafe but useful” http://channel9.msdn.com/showpost.aspx?postid=326762. It’s pure self deprecating humor. Haskell is useful. See Darcs as a very practical example of what Haskell can do.