IMC Trading Java Developer Interview Questions
& Process

One of the weirdest interview experiences ever, I got rejected even after solving everything. I want to help others avoid this. It started with a take-home assignment: a simple and garbage-collection-efficient rock paper scissors game. This was followed by Interview 1, which focused on Java core concepts. Then, there was a 2.5-hour coding challenge involving a matching engine problem. The task was to code it simply and pass 44 test cases, which I did. The interviewers were furious that I used my own strategy to pass all test cases and ultimately rejected me. They insisted on running test cases even when the code wasn't fully complete. I managed to pass all of them with 7 minutes to spare, yet I received a rejection with mostly negative feedback, primarily citing that I wasn't listening to them.

So the hiring process includes an online assessment with three simple Java problems, then a one-way video interview, followed by a first round interview, and then a final round interview, after which they extend an offer. It's pretty standard for the industry and not too difficult.

Had a phone call with HR first. Then, a weekend take-home task, pretty abstract with no clear criteria, to build a Rock Paper Scissors game. Next, a Skype interview with two engineers where we talked about Java basics and my weekend task solution. The onsite interview had multiple parts, and I was rejected after the first two. The first part involved analyzing a Java trading project (10-20 classes), explaining its purpose and implementation details like queue sorting and order matching. I also had to modify the code for a new order matching algorithm, with about 50 minutes for this. The second part was about algorithms; no coding, just verbal explanations and whiteboard drawings. I got two tasks after some theory questions. One task was to figure out how to differentiate between 1-byte and 2-byte encoded characters and remove the character from a text file, which felt a bit odd for a Java dev. I don't know what happened after, as I was rejected.