I'd personally prefer to not adopt Heroku's nonsensical superhero terms, since we already have common terms for these things that make sense -- application cont

I'd personally prefer to not adopt Heroku's nonsensical superhero terms, since we already have common terms for these things that make sense -- application containers, applications. PaaS is "platform as a service". A way of automatically deploying, updating, and managing applications inside of application containers running on a cluster of machines, using either processes, virtualization, or OS-level process containers. Amazon BeanStalk does this for Java by using Tomcat running in a EC2 VM, and exposing the servlet interface such that one can deploy Java webapps directly to BeanStalk. Google App Engine did the same thing for Java, and with some custom packaging for Python. The whole idea is to get rid of all the textual OS configuration files and vestigal limbs of UNIX and get down to the simple bare metal fact that we tend to treat the OS as a hardware abstraction layer for a single application.