PayPal Software Developer Intern interview questions

Was contacted by the recruiter to set up the technical phone call interview. The interviewer was the coolest guy I've ever been interviewed by. He asked me only on the current project I'm working on because the position is very specific to it. It went really good, and two business days later I got a mail from the recruiter saying that they'll be offering me the position.

Got a screening phone call involving coding, followed by onsite interview. Most question at onsite were on data structures, and algorithms. And one question on designing why interface are needed for the design of the system.