Spring has always been one of the cleanest frameworks in the Java enterprise world. It makes sense that someone would use it as the foundation for a Java cloud.
That someone in this case is SpringSource, one of the Cloud Foundry project leaders and a division of VMware. It should come as no surprise that this cloud is built on top of VMware virtual machines.
The VMware-hosted Cloud Foundry is a bit of a departure from past offers. The first version deployed Spring apps to the Amazon EC2 cloud. It's still available from classic.cloudfoundry.com if that's what you want.
The easiest way to use Cloud Foundry is to create a Spring project from a template with SpringSource's customised version of Eclipse called the SpringSource Tool Suite. I tried installing some of SpringSource's tools into my own version of Eclipse, but the right collection of libraries was not easy to find. The SpringSource Tool Suite is simpler.
The Cloud Foundry is not limited to Spring. There's support for Rails, Sinatra, Scala, Grails and Node.js. It's all running on the JVM even if you don't write any Java. Cloud Foundry just announced PHP and Python/Django support as well. The VM image that you get also comes ready with MySQL, MongoDB, and Redis databases waiting to suck up your information.
You can download the Micro Cloud Foundry, a portable virtual machine image of the Cloud Foundry environment, and run it on your own system with VMware Player.
The core code is open sourced at cloudfoundry.org and largely covered by the Apache licence.
VMware has kept mum about the pricing. The product is still in beta, and VMware has been kind enough not to charge for it. Will the rates be too high? How can you plan? You can't, but the Cloud Foundry virtual machine is fairly open.