One question that might come to mind is, if Mobicents exists, why would Ernie?
Well, that's an excellent question. From where I sit, I would answer it like this: If C++ exists, why then have Visual Basic? Well, the answer to both is that sometimes you need to script a solution, and sometimes you need to build it from the ground up. Scripting is excellent for smaller applications and for integration with a bunch of technologies, components, etc. Fully featured development environments are a must for any sort of large feature development, or ones that involve many developers. Mobicents is an implementation of JSLEE, as are offerings from Ubiquity and others. Chances are though, in my office inside a small ISP, the web developer would really, really rather see a Python or TCL API than Java.
There's really room for both.