Of course you can! It'll all depend on what career choices you make. If you become a software engineer to then go develop corporate Java software for Big Corporation Inc, then you won't have much of an impact. Join a startup with a valuable vision and a good product and you definitely will.
I just wanted to give my perspective, as someone who's done both, regarding 'working for a product you love' and 'working for a big company because you get paid well'.
If anyone got personally offended because they think they can be a corporate Java developer and change the world by contributing to a charity... well, I guess it's pretty clear the OP wasn't asking about that. Anyone can do that, no need to be a software engineer.