30 minute interview

I interviewed for a company about 6 months ago for a position as a graduate/student software developer. The interview lasted an hour and a half (half an hour being a written test on c++ and java). And I was asked for general knowledge on all technologies (grid, sockets, servers, classes, objects, linux etc).
I didnt get that job, but they called me a few weeks ago, and asked me to do an aptitude test. A few days later, I was asked to go for another interview for a graduate training program.
The interview will be a 30 minute aptitude test (similar to the online one), followed by a 30 minute face to face interview. What can I possibly expect to be asked at this stage?
Thanks in advance.
merlin

Merlin,
What country are you in?

Darn "aptitude tests" are completely useless. If I believed them I am completely useless as a programmer and should find work outside IT immediately. Of course when I mentioned some of the questions to friends who work in other industries they remembered having the exact same questions asked of them as well...
The 30 minute interview will likely be little more than you waiting for the results of the test and them telling you whether you can come back for the next round or not, at least that's my experience with such "test".

maybe they are just playing you for a fool , waste all your time and then give u some false sense of possibly getting the job and in the end just tell u with some simple email that u didnt get accepted.
I had experience like that