For years the main JVM advantage was the portability, then Microsoft released Dot Net using the same VM approach trying to get some portability too. But nowadays with VMWare, Xen, VirtualBox, etc … with OS Based Virtualization in general, there is no problem with the portability issue. So the advantages of JVM or CLI environments must be evaluated from other perspectives:

1. Usability
2. Development productivity
3. Scalability
4. Security
5. Reusability
6. Performance
7. Standards compliance
8. Community support
9. Costs and ROI

Virtual appliances are easy to install, easy to manage and easy to restore if there are any problems. The developer is free to select his favorite OS for the development and the customer is free to select his favorite OS for runtime.

- The battle of platforms Round I was portability (IT centric topic)
- The battle of platforms Round II will be Productivity, Time to market and ROI (Business centric topics)

Now the problem is that in few years you will be running all your applications on two levels of virtualization. For example a Java application running on a guest Linux running on a Windows host. or a Dot Net application running on a guest Windows running on a Linux host.

Paradox: Maybe it is time to go back to native compiled code because there will be no real machines anymore in the world.