His argument is hearsay. There's no conclusive evidence that a stack-based VM will always perform worse than a registered based one. There are tradeoffs between

His argument is hearsay. There's no conclusive evidence that a stack-based VM will always perform worse than a registered based one. There are tradeoffs between both designs. With all of the optimizations you see from register based VMs, you end up with larger instructions due to the lack of a stack pointer. You can claim that the JVM runs faster than Dalvik though, because it has a better JIT that has had years more to improve. But I don't know why JVM is being compared against Dalvik when ART is where Android is going in the long run, and has AOT compilation that beats Dalvik's JIT.