Here in Germany a quite popular developer magazine called "JavaMagazin" is published once a month. I'm a regular reader and a few days ago the latest issue was in the mail (yes, the "real" mail :)). The headline on the front pagewas about Clojure, a quite new language for the JVM. A few issues before, the headline was about Scala. Also a quite new language for the JVM. Again before it was Groovy. Personally I get the feeling that some kind of programing language inflation takes place. The question comes in mind if this makes sense or not.
I've read several posts and articles about this phenomenon. Sometimes it is discussed in conjunction with the term "polyglot programmer". The idea behing this term is that you as a developer should learn permanently new languages. By doing so you are supposed to somehow look behind the scenes and get a better programmer by learning from the different abstractions that are used in the different languages. This sounds not bad to me. If you are a skillful programmer you probably are able to improve your skill level this way. You probably could do so by reading books about programming concepts, too, but learning new languages is definitely more fun.
Additionally, the concepts of new languages are sometimes really able to improve the quality of our work. This happens, in my opinion, when a new language is able to transport a theoretic concept out of the computer science ivory tower to real world. In my opinion, Java did exactly this for object oriented programing (and some other concepts like garbage collection and virtual machine execution). Now, if people invent languages like Clojure, they enable programmers to easily use the concepts of functional programming in their projects. Since Clojure is based on the JVM it has a lot more chances to really succeed in this task than, for example, Lisp. Who knows, maybe in ten years from now the majority of the development community has moved on to functional languages. One possible reason for that move might be that increased parallelized hardware simply called for new programming concepts. From this point of view, the invention of new languages is a must and absolutely makes sense.
On the other hand, the inflation of programming languages is a massive problem for businesses that consider software as an investment. Even if a new language decreases the overall costs of a new software system by, lets say, 20% (which is a LOT and not realistic), the savings will be eaten up in the maintenance phase quite fast. You'll need either more people with different language skills or the same amount of people with increased skills. Both variants are more expensive that maintaining systems just in one language.
Today its easy to focus on Java or .NET or even C++ as the main programming language in a company. At least my customers try to focus their IT investments this way. The more programming languages evolve, the more difficult it is to enforce a focused technology selection. A lot of discussions pop up around the language selection process right now and these discussion will be more intense the more languages enter the market. From this point of view, language inflation is anything from positive. It makes IT projects even more complicated and risky than they are right now (risky, because you easily could choose the wrong language for your problem domain).
As a software architect I cannot simply put away the arguments of the people that are focused on the figures. Developing systems is fun, but at the end of the day they are just investments. So here's how I handle this dilemma. I agree with people that argue that a developer should learn new languages regularly. Probably not a new language a year or even more - I simply am not able to handle this. But every two to three years I try to grasp one of the popular languages and see what happens. A few years ago I did this with C# an threw it away afterwards. It simply is not relevant for my business. The last time I chose Groovy and this was certainly one of my best decisions lately. Groovy has saved me tons of times in several projects since then. Just if you are curious: I never used Groovy for a production system until now. But I use it regularly to pimp my development infrastructure. This infrastructure is only needed during the development phase, not for maintenance. If something of the Groovy stuff is really relevant for maintenance, I convert it to Java before shipping it to the customer. I do this because I believe that in maintenance phase things must be simple to be cost efficient. Two programming languages (Java and Groovy) for one system are not simple, hence I avoid this.
Now, if someone argues we should use a brand new language like Clojure for a given project, because it is cool and certainly better than good old Java, I am very cautious. Java is a suitable language for most requirements in IT business I am aware of, so introducing something new for productive use must be evaluated very carefully. Typically, this evaluation results in keeping Java. But if the arguments are valid, like, for example, the need for massive parallel execution of the internal processing, I certainly would not disallow the usage of Clojure just because it is new.
