The Java language is dying. Most people do not yet realize this yet, but it is inevitable. What do I mean by dying? Why do I think it is dying, and why is there lots of hope? Dead languages
So what do I mean by dead? First of all, languages do not die just like that. There are still people programming in Cobol, and likewise, there are still people that can read old Greek fluently. But just like Cobol and every other programming language, Java will at some time be left to the dinosaur programmers. I think that Java is currently at its peak (or will soon be), and will go downwards from here. It will take some time, but the signs are there.
First of all, there is the rise of dynamic languages. They have been around for quite some time, but all of sudden there was Ruby on Rails. Many Java programmers bit the bullet and switched to be rewarded with a up to 10 times productivity boost. There are those that say this can be attributed to dynamic typing. I believe this is not the case. I think the boost is possible because the Java language is quite weak compared to Ruby; the same problem can be expressed in a lot less lines of Ruby then lines of Java. This has nothing to do with typing, but everything with how the language is structured.
Secondly, there is the way Java is extended over time. The extensions have been done with great care. This has paid off: Java is still mostly a clean and simple language. Even with the tiny changes, each new version brought its problems. The largest change so far has been the introduction of generics. I see generics as an improvement, but as I wrote earlier, they can be a pain to use.
And now there is the closures debate. Some people (like James Gosling) want to have them at every price. Others (like Joshua Bloch) say that the complexity budget has been used and that Java is not ready for big changes like closures. I agree with the latter.
Despite the care with which Java was and is being extended, the possibilities for doing so are reaching zero rapidly.
There is hope!
If there is one gem coming out of the Java world, it is the Java Virtual Machine. With each release the JVM has brought performance improvements. And this is likely to continue for the next versions. The JVM is still climbing and is nowhere near its peak. This can be proved by looking at the many languages that now run on the JVM. Everything from PHP, Lisp, Cobol to Ruby and Python. Some of these (in particular Ruby) are very well supported by several IDEs.
The Java language does not need closures or other more advanced stuff, there are many languages on the JVM that already provide those things: Ruby, Python, Lisp and Scala.
Yes, now there is Scala! Scala is a language for both the JVM and the CLR. Scala's syntax is as concise as Ruby's. It provides a very smooth transition from the Java language, but nevertheless is a complete functional language while at the same time staying purely object oriented and statically typed. And, as I learned at Javapolis, its library is already excellent, and even better: without any particular optimizations Scala programs outperform Java programs on the same JVM! What is not to like about Scala?
Many statements in this article are based on personal observations and anecdotal evidence.
Update 2007-12-24: Despite the tone of this article, I am still writing Java and foresee to do so for quite a bit longer. And note: having fun doing it!