- "Write once, run everywhere." as the sibling poster mentions. I can build on my Mac, deploy on whatever the server platform is.

Snapshot and release builds of our build server are distributed via a Nexus-managed repository. So, everyone codes against exactly the same dependencies, regardless of the platform.

- Hotswapping/JRebel.

- Good interoperability with other languages. E.g. the Typesafe folks implemented Akka in Scala. Java gets it for (well, almost) free.

- Easy monitoring and instrumentation.

Obviously, there are downsides as well, such as startup times (twofold: starting the VM and Hotspot detection/compilation), preset heap size, expensive JNI (native interface), etc.

Well-defined semantics, including for "errors" like integer overflow or null dereference.

A community that's converged on a deterministic, crossplatform way of representing library dependencies (maven).

An ABI that includes a notion of objects, which makes cross-language interoperability with objects easier (though counterbalanced by not having a cross-language notion of functions).

Definitely deployment flexibility. Write on OSX, Test on Linux, Run on Solaris.

But also performance. JVM can be faster than say C/C++ code in many cases.

"Write once, run anywhere"

Yeah, it's the Java culture and the stuff bolted on top by Sun and other business software vendors in an effort to keep relevant and appeal to CIO:s.

But I don't agree with the prediction: Python and JavaScript aren't really drowning in BS produced by architecture astronauts. It exists but it's not prevalent.

Java platform has already had plenty of reboots.

Play, Grails and Vert.x have shaken up web development. Scala, Groovy and Clojure for languages.