Today I was reading two articles on TechCrunch and GigaOm speculating on the upcoming support for Java on Google App Engine.
There are a few reasons (presented below) why I cannot call these 2 articles pure speculations, but I really doubt that GigaOm has any confirmation about it even if they're saying they have one: (TechCrunch doesn't make any such claims):
We are trying to get more details. [...] but we can now confirm that it is going to happen. We have have confirmed the news and expect the announcement later this spring,
Have you heard before of any unofficial confirmations coming from Google about their unreleased projects?
Anyways, let's see why I do think that Java may be in fact the next language on the Google App Engine.
Already on the roadmap
Google has already announced in their App Engine roadmap that they will add support for another language and as we already know, at Google the 3 official languages are: Python, Java and C. Python is already available on the Google App Engine, so Java has at lest a 50% chance of being the next.
Top Requested Language
By looking at the Google App Engine Issue tracker you'll notice that quite a few languages are requested by the community and Java is leading with 2000+ votes:
While I don't believe Google will base their decision on a community request, the community is sometimes good at figuring the future.
Virtual Machines vs Native Code
Java is running on the virtual machine and controlling a virtual machine is definitely easier than restricting/limitting native code. Remember that what currently runs on Google App Engine is a reduced Python.
Secondly, Google has experience building a custom Java VM: see Android's Dalvik.
Java is the Most Popular Language
I know this might be debatable, but there are many reports showing Java as being the most popular language.
So, while I think those 2 articles are speculating, things may in fact become true and Java will be available on Google App Engine.