Homemade JVM

It seems that the author was trying to create his own, but limited, Java Virtual machine(JVM). He seemed to be torn between working with another project he had going called Morpheus and the JVM. His coding was above anything I have done or seen so far. It was an interesting read and I tried following along with how he broke down each section. Still though, it is quite a bit to digest at my current level. If there is a JVM available, not sure why someone would want to build another one from scratch. Guess he liked the challenge.