The term microkernel has a specific meaning, from operating systems research, and that meaning does not seem to be relevant to NetKernel in any way. Their use of the term kernel also seems dubious, but at least that is a general term used in different ways in different parts of the software world, so they can more reasonably appropriate it to apply to their project. (Maybe all this would seem less silly if microkernels, in the true sense of the word, were more widely seen as a good thing.)
I'd like to dismiss this as the usual marketing stupidity, but the misuse of the term continues even in the technical documentation.
You also need to dig through their web-sites and documentation to discover that, while the concept may not be specific to Java, the current implementation certainly is . But surely this is important informantion for any potential customers? My guess is that they want to avoid the question of why they don't implement apparently-relevant standards from the Java world such as the Servlets API. I hope that the answer is that they are doing innovative things that don't fit inside those standards. It would be nice to see this explained properly.