For general purpose computing, Go is catching up and beating Java in some performance benchmarks.
For web application development, Ruby and Python have come with less ceremony for years compared to Java and J2EE. Also, Javascript with Node.js and the exploding ecosystem around JS frontend frameworks make Java less relevant.
For concurrency-related challenges, FP alternatives like Scala and Clojure are winning hearts and minds while allowing people to continue to utilize the mature, solid parts of the JVM ecosystem.
One area where Java remains dominant is in Android development, but the language doesn't seem to be evolving there in comparison to the way ObjectiveC is evolving alongside iOS.
Learn Java in Minutes (73 points, 2 days ago, 50 comments) http://news.ycombinator.com/item?id=5969685
"Practical Artificial Intelligence Programming With Java" by Mark Watson (91 points, 4 days ago | flag | 41 comments) http://news.ycombinator.com/item?id=5963448
That combined with some of the blunders associated with it's management and of course, Oracle being Oracle, it's not really as attractive as it once was.
That said, I'd imagine that it will still be around and popular for some time, but I wouldn't be surprised if it fades in popularity.
With the number of financial institutions that have systems build on Java (for good reason, its mature, performant, has many many tools an frameworks) as well as many other organisations, I don't think it's going to disappear any time soon.
On the other hand, there are many languages, databases, and frameworks that are regularly crop up on HN over time that will probably disappear soon. But they are more interesting to talk about so they make the news.
You can ask the same question for C,C++ - people use those too. And right; will we talk about Ruby and Python in the next five years?
Some would argue python has entered into more of the mainstream now and the "python" PG refer's to in that article is probably different now (Go, Scala, Clojure, Haskell, etc. come to mind)
But the spirit of the article is still correct