Applied online through LinkedIn and received a call from a recruiter regarding next steps. Soon after, I was scheduled to talk to a Senior Software Engineer for a 45-minute technical interview.

Questions included:

• Basic resume drilling
• OOP theory questions
• Multithreading, synchronization, and deadlock
• Why is String immutable?
• Config files in Hibernate

Next, I got a call for an onsite interview a week later. I met with three Senior Software Engineers and one Product Manager. She took me to lunch, but while we were eating, she had me do a coding exercise on a whiteboard, which I thought was odd and impolite. Rushing through it, and she wasn't really helpful during the interview. Finally, I met with HR.

Some questions included:

• Static/non-static variables/methods, final
• How would you sort a very, very large file?
• Basic data structures
• Design a basic inventory system

Write code to do the reverse mapping from a phone number to all its possible letter combinations. For example, if '12' is dialed, all possible combinations will be 'ad', 'ae', 'af', 'bd', 'be', 'bf', 'cd', 'ce', 'cf', and so on.