I've been thinking about this off and on over the weekend. And one thing I kept coming back to (even disregarding ideas about the technical future that my eight-month old keeps stealing from my mushy brain) is a discussion of community and open source. Has there ever been a development platform that died out having such a large and diverse open source community?
People who are firmly in the scripting camp and have never used Java may not realize the size and scope of the community. That may be because there's no central repository (like CPAN), or because there are so many large companies out there that might look to the naive to steal the oxygen from the ecosystem.
But right now I think of the Java community identically to how I think of Perl and CPAN: if there's some system I need to talk to, or some general task I need to accomplish, there will be an open source, business-usable library out there for it. I have bet my technical future on this with both platforms and haven't been disappointed yet.
Further, dismissing Java-the-language but grudgingly accepting Java-the-platform makes no sense. If I'm running JRuby, or Scala, or plain old Java, the community and the wealth of libraries is what supports my project and team.
Lastly and IMO, that the official JDK is open source makes it that much stronger. And that all editions of the platform , from mobile phones on up, are open source is underappreciated because of the carping that it took them too long (it sure did) and there are apparently some leftover licensing issues (IANAL). One of the wonderful things about open source is that people pretzel your project in areas and ways you never anticipated, and that all those pretzels produce benefits you can't even conceive. I think we'll see lots of these in the next few years, particularly as mobile devices get more powerful and people start playing with little dev kits that can run Java.
I have some other thoughts on this general topic (mostly related to the amount of risk projects/hiring are willing to assume with other platforms), but I'm going to have to wait a bit on those. Hopefully my eight-month old won't steal those, too.