It is relatively simple to figure out if a graduate has solid understanding the basics irrespective of their 'language' group. These fundamentals include 1) Data Structures 2) Operating Systems and 3) Algorithms and their Complexity. These are essentially conceptual areas and discussing design or approach towards a particular problem in these can reveal how strong or weak they are. You dont have to make them write code.
I would say that if anyone has a strong base in these fundamentals, and equally importantly has a positive attitude, he can learn any other language.
I always go for these fundamentals and their evaluation - fresh grad or experienced. These are the primary criteria to get someone hired.
