As someone who's primarily a "Java schooler", and a pretty recent graduate at that, I definitely think it'd be possible for me to learn C or C++ without too much pain...
However, I really don't want to. I can only speak for myself, but C can be a pretty ugly language if you've grown up with Java. I think motivation is going to be the bigger obstacle. Motivation and maybe some whining about that "in Java this is soo much easier, why isn't C Java?" :)
If you can find someone with the proper motivation, the rest will work out okay. :)