I have two 45 minute interviews at my university. They were back to back interviews with two recruiters. They were basically straightforward technical questions, about things that you learn in class. They first started off asking about me and I described my major and my interests. Then they asked general technical questions, like what is the run time of this data structure and what is the difference between C and Java.
After, they asked me to write a program on a paper. They wanted to hear your thought process so they ask you to describe what algorithm you would use before writing it. The interviewers ask you several ways that the program can be written and ask you to choose the best way. They basically want to see that you know how to write code and formulate an algorithm in a short amount of time. The questions aren't too hard because you only have 45 minutes.
The interviewers were really friendly and I didn't feel intimidated or nervous when talking to them. I had a deadline for another offer and they were really accommodating. They got back to me in 2 days. Overall, the interview is pretty straightforward and you shouldn't stress out about it.