Just because a developer utilizes the JVM doesn't mean they're writing in Java. As I recall Twitter uses and is a big proponent of Scala, which sits on top of the JVM.
I agree. Java as a language has been abusively used (+XML), just like any other popular languages. But the JVM is very solid and luckily we can use other languages other than Java. So you get the best of both worlds :) I use Groovy and Scala for personal projects, but at work I still use Java.
You guys are never reading the OP submission: In the article the architecture of Twitter is a bit explained.
I most certainly did read the OP submission. Perhaps you meant to address the parent?