If you are going to put a lot of Java programmers straight out of college to write production code, I'd say the first thing you should be concerning is pointers and memory management.
Really, those who come directly from managed code rarely have the skills to debug pointer-related exception, let alone use it correctly, or even understands how their language/tools utilize it.
Pointers is how you think not just write code.
The framework and coding practices can be taught as tips and notes along the way.
But failing to understand pointers when writing C code is just waiting to shoot yourself in the foot, if not the head.
