Java's days are numbered as a language for new development - Viva la JVM!!
I got the sense that you should at least start thinking about an exit strategy. Stuart Halloway was even more outspoken: "Don't use Java for new greenfield development." (Saying that any of the talked about alternatives are better - Scala, Clojure, Ruby and Groovy).
After going to a few sessions that dealt with concurrency, I am certainly not inclined (border-lined scared) to do that kind of stuff in Java. The two languages most talked about at the conference were Scala and Clojure.
The nice thing is, that both language run on the JVM, so you can use the new language features, but are also able to use the vast power of Java libraries, if needed. Once drawback I saw is the fact that both Scala and Clojure can be fairly cryptic, which was an issue that was raised repeatatly by the audience and as well during conversations with fellow developers in between session breaks. Scala at least gives you the ability to write Java like code and then later on as you gain proficiency, you can make your code more concise . From a "power perspective", Scala looks awesome, though.
The sessions I atended to today were:
- Tackling Concurrency on the JVM (Venkat Venkat Subramaniam)
- Advanced Topics in JMS (Mark Richards)
- Java.next: Clojure, Groovy, JRuby, and Scala (Stuart Halloway)
- What's New in Spring 3 (Ken Sipe)