If you're interested in learning Java, then I'd highly recommend http://www.bluej.org/objects-first/
- the latter isn't out yet but either one would give you a good introduction to Java and OO programming in general. Greenfoot is especially fun to start off with
From then on the sky is really the limit as to how programming goes!
As for troubleshooting / technician duties then there's various courses you could go on, or if you're not worried about official certification then just hanging around here and looking at common problems that come up and how they're solved would get you some experience. I'd also do some reading up on the different components within a system if you haven't already, common failure points, how they fit together, what they do - that sort of thing. There's a number of good books around for that as well, and some good guides on the internet (but as always, don't always take what's said as the truth unless you're 100% sure it's from a trusted source.)
My advice would be to pick up a good book or 2 on a subject or 2 that you're interested in. That way you've got a reliable source of information, and if you're not sure about anything you can always ask here