By and large, I'll need to make existing web apps mobile friendly (ie., easy to use on a small mobile browser), rather than write apps for a particular mobile d

By and large, I'll need to make existing web apps mobile friendly (ie., easy to use on a small mobile browser), rather than write apps for a particular mobile device per se. So core programming languages will probably still be Java and Ruby. I expect that HTML5, CSS, Javascript, other UI type languages will factor in as well.