Liferay Software Engineer, Technical Support interview questions

Met a guy with the SE : Tech Support role at a career fair. Told him I'm interested in applying. Gave him my resume. A few days later, a recruiter gives me a phone call and we talk about general career goals, other behavioral questions. He tells me about the next stage, a technical challenge, where you have to design a shopping cart(detailed below). Not too hard, just had to brush up on Java a little bit. Next I'm told that I passed the technical challenge and that I'm invited to an on-site interview. Liferay was nice enough to pay a generous 54 cents/mile gas compensation for my 40 mile trip to their Diamond Bar office. The building was modern, with lots of open space, a lively atmosphere, and many young people working there. I met with 3 senior SE:TS employees to talk about my career goals, my projects, resume, etc. Technical challenges(detailed below) were fairly straightforward. All technical challenges were in Java, so make sure you remember the basics and how it differs from C++ if you're more familiar with that. I then met with the SE:TS middle manager and we talked more behavioral stuff. Finally, I met with the founder who I didn't know was the founder until after I talked to him, whom I talked with about my academic background and some other light stuff for a few minutes. Fairly pleasant experience, although a little bit awkward, but mostly because it was my first on site interview. One tip I would have is that even though the technical challenges are pretty straightforward and are on a piece of paper, talk through them with the interviewers.