Technical Interview Report: Senior Software Engineer at Bloomberg - Spring Boot Stack (4 Rounds)

If you are prepping for a Senior Software Engineer role at Bloomberg, you'll want to buckle up.

I recently went through their 1-hour technical screening, and it was a dense, fast-paced session that touched on everything from high-level architecture to LeetCode-hard problem-solving.

Here is the breakdown of what to expect and the specific technical challenges I faced.

The Interview Structure:

The session was strictly timed at 60 minutes, divided into four distinct segments:

1. Project Deep Dive: A discussion on my previous experience and architectural decisions.
2. SQL Assessment: Relational database querying.
3. Data Structures & Algorithms (DSA): Live coding.
4. Spring Boot Practical: A hands-on look at REST API design.

Part 1: SQL - Aggregations and Filters

The SQL portion wasn't designed to trick me with obscure syntax, but rather to test my comfort with window functions or subqueries.

The Challenge:

• Given an Employee table (id, department_id, salary) and a Departments table (id, name);
• Find the department(s) with the highest average salary.

Key Constraints:

• You must return only the max average.
• If there is a tie between multiple departments, you must return all of them. Tip for others: Don't just use LIMIT 1. Make sure your solution accounts for ties by using a HAVING clause or a RANK() window function.

Part 2: DSA - The "Hard" Wall

The interview took a sharp turn into high-level algorithmic thinking. I was hit with Sliding Window Maximum (a well-known LeetCode Hard). The goal is to find the maximum value in a sliding window of size k as it moves across an array.

For a Senior role, they aren't looking for the 𝒪(nk) brute-force solution; they want to see if you can optimize it to 𝒪(n) using a Deque (Double-Ended Queue) to keep track of indices in a monotonic fashion. If you are rusty on monotonic queues, brush up before interviewing here.

Part 3: Spring Boot - Annotations and API Design

Because this role requires strong Spring Boot expertise, the final segment was a "sanity check" on my framework knowledge. I was asked to live-code a sample REST API.

Focus areas included:

• Proper use of @RestController and @RequestMapping.
• Dependency Injection via @Service and constructor-based injection.
• Handling HTTP verbs and path variables.

Final Thoughts

Bloomberg seems to value "T-shaped" engineers-people who have the high-level Spring Boot context but haven't forgotten how to handle complex algorithms or raw SQL.

My advice? Practice your sliding window logic and ensure you can talk through your past architectural choices clearly and concisely.