In order to understand the issues you might have with an application you need to have a decent understanding of its runtime environment. From the hardware on up. The JVM adds a huge new runtime that you need to understand how it works and its possible failure points in order to be able to effectively develop software and diagnose issues. So, IMO, it goes against the basic precept of software engineering. That of taking a problem and breaking it down and simplifying it in order to develop a well understood, maintainable systems. You don't simplify something by adding complexity.