I'd probably try to emphasize "left to go do a startup" on your resume, whether or not it works out, whether or not you approach it as an 80 (or even 40) hour/week thing, rather than "took time off".
But, otherwise, this is absolutely good for your resume, I think. Assuming there's no huge change in the market, you should be as employable if not more. Maybe try to stay involved in the .NET/J2EE developer community once a month or so, keep in touch with former coworkers, etc. in case you decide to go back to that instead of mobile, though.
But, otherwise, this is absolutely good for your resume, I think. Assuming there's no huge change in the market, you should be as employable if not more. Maybe try to stay involved in the .NET/J2EE developer community once a month or so, keep in touch with former coworkers, etc. in case you decide to go back to that instead of mobile, though.