Yes Java runs on the mainframe and runs quite well. CICS can run JVMs which can provide web services using Axis2 as well languages like PHP, Groovy, Javascript

Yes Java runs on the mainframe and runs quite well. CICS can run JVMs which can provide web services using Axis2 as well languages like PHP, Groovy, Javascript (via Rhino) or Java for CICS apps. Websphere runs on the mainframe but it's a bit different than what you find in the distributed world. The JVM that would normally run an application on x86 is broken into two parts the controller and the servants. The controller will work in conjunction with workload manager to deliver incoming work to a number (you configure) of servants which then process it. With this new mainframe it looks like it will have support in hardware and software for JVM's that can self reconfigure on the fly depending on what work needs to be done and what the current load is. I would like to read more on that.