I've mentioned before, but I think we are living in a period of time where a bigger explosion of programming languages is occurring than at any time in the past four decades. Having lived through a number of the classic languages such as BASIC, Simula, Pascal, Lisp, Prolog, C, C++ and Java, I can understand why people are fascinated with developing new ones: whether it's compiled versus interpreted, procedural versus functional, languages optimised for web development or embedded devices, I don't believe we'll ever have a single language that's right for all developer requirements.
This Polyglot movement is a reality and it's unlikely to go away any time soon. Fast forward a few years we may see a lot less languages around than today, but they will have been influenced strongly by their predecessors. I do believe that we need to make a distinction between the languages and the platforms that they inevitably spawn. And in this regard I think we need to learn from history now and quickly: unlike in the past we really don't need to reimplement the entire stack in the next cool language. I keep saying that there are core services and capabilities that transcend middleware standards and implementations such as CORBA or Java Enterprise Edition. Well guess what? That also means they transcend the languages in which they were written originally.
This is something that we realised well in the CORBA days, even if there were problems with the architecture itself. The fact that IDL was language neutral obviously meant your application could be constructed from components written in Java, COBOL and C++ without you either having to know or really having to care. Java broke that mould to a degree, and although Web Services are language independent, there's been too much backlash over SOAP, WSDL and friends that we forget this aspect at times. Of course it's an inherent part of REST.
However, if you look at what some are doing with these relatively new languages, there is a push to implement the stack in them from scratch. Now whilst it may make perfect sense to reimplement some components or approaches to take best advantage of some language capabilities, e.g., nginx; I don't think it's the norm. I think the kind of approaches we're seeing with, say, TorqueBox or Immutant where services implemented in one language are exposed to another in a way that makes them appear as if they were implemented natively, makes far more sense. Let's not waste time rehashing things like transactions, messaging and security, but instead concentrate on how best to offer these capabilities to the new polyglot movement that makes them fit in as first class citizens.
And to do this successfully is much more than just a technical issue; it requires an understanding of what the language offers, what the communities expect and working with both to fit in seamlessly. Being a Java programmer trying to push Java services into, say, Ruby, with a Java programmers approaches and understanding, will not guarantee success. You have to understand your users and let them guide you as much as you guide them.
So I still believe that in the future Java will, should and must play an important part in Cloud, mobile, ubiquitous computing etc. It may not be obvious to developers in these languages that they're using Java, but then it doesn't need to be. As long as they have access to all of the services and capabilities they need, in a way that feels entirely natural to them, why should it matter if some of those bits are hosted on or by a Java application server, for instance? The answer is that it shouldn't. And done right it means that these developers benefit from the maturity and reliability of these systems, built up over many years of real world deployments. Far better than the alternative.