Had a phone call with the recruiter, then scheduled another phone call with the hiring manager. They talked about their company for a bit at the start of the call, then asked me questions about my resume, then asked technical theory questions about java and OOP. Then at the end he asked me to get out a pen/paper to write a function to for a scenario

First, I had a brief phone interview that was lightly behavioral. It was not a difficult interview honestly. After that, I had a over hour long technical interview. The first part covered questions about projects I have worked on, and then it went into pretty simple Java interview questions (encapsulation, inheritance, etc.). However, the difficult part came with the System Design questions. I was asked to design a system for employees (software developer and quality assurance types) that are either salaried or hourly using classes. I admit I was not really prepared for this part of the interview and I am not surprised I did not get the offer. However, I do feel a phone interview for System Design is not the best format.