Sunking Software Engineer interview questions & guide 2026

The following questions are representative of the technical rigor you will encounter during the Sunking interview process. While these are based on recent candidate experiences, use them as a framework to assess your depth of knowledge in Java and SQL.

Java Backend Foundations

This category tests your core understanding of object-oriented programming, design patterns, and the Java ecosystem.

• How is dependency injection achieved and what are its advantages?
• What are the fundamental differences between an abstract class and an interface?

Preparation at Sunking requires a balance of theoretical mastery and practical application. Do not simply memorize definitions; be prepared to explain the "why" behind your technical choices.

Role-related knowledge – You must demonstrate a deep understanding of Java backend architecture. Interviewers will look for your ability to explain concepts like Dependency Injection in the context of real-world framework usage, such as Spring.

Problem-solving ability – When faced with SQL or design challenges, approach them systematically. Clearly state your assumptions, explain your reasoning before writing code, and consider edge cases that might impact performance or data integrity.

The Sunking interview process is designed to be efficient yet thorough, often beginning with an AI-driven technical screening. This initial stage is a critical filter that assesses your fundamental knowledge before moving to human-led discussions. You should expect a focus on technical competency, logic, and your ability to articulate complex concepts clearly under pressure.

This timeline illustrates the progression from automated technical screens to more comprehensive assessments. Use this to pace your study schedule, ensuring you have a strong grasp of core fundamentals early on, as these form the bedrock of later-stage interviews. Keep in mind that while the process is standardized, the depth of questioning may vary depending on the specific team's technical stack.

Java Backend Architecture

We evaluate your ability to write modular, testable code. Mastery of frameworks is expected, but understanding the underlying principles is what sets top candidates apart.

Be ready to go over:

• Dependency Injection (DI): Understand constructor injection vs. setter injection and how DI containers facilitate loose coupling.
• OO Design: Be prepared to discuss polymorphism, encapsulation, and when to use interfaces to define contracts.
• Advanced concepts: Experience with Spring Boot lifecycles, bean scopes, and proxy patterns.

Example scenarios:

• "Explain how you would refactor a tightly coupled legacy module to use dependency injection."
• "Describe a scenario where using an interface prevented a circular dependency in your code."

SQL Query Proficiency

Your ability to manipulate data efficiently is paramount. We look for candidates who can solve problems without relying on inefficient, nested structures.

Be ready to go over:

• Set Operations: Understand the differences between UNION, INTERSECT, and EXCEPT/MINUS.
• Joins: When to use LEFT JOIN vs. INNER JOIN to isolate data discrepancies.
• Performance: Understanding how indexes affect query speed for large datasets.

Example scenarios:

• "How would you identify orphan records between two tables without using subqueries?"

As a Software Engineer, you will primarily focus on the development and maintenance of high-availability backend services. You will spend a significant portion of your time writing clean, documented Java code, designing database schemas, and ensuring that our services can scale to meet the demands of our growing user base.

You will also work closely with product managers and data teams. This involves participating in code reviews, providing technical feedback on product roadmaps, and troubleshooting production issues. You are expected to take ownership of your features from the design phase through to deployment, ensuring that every line of code contributes to the stability and reliability of the Sunking ecosystem.

We are looking for individuals who combine technical excellence with a collaborative spirit.

• Must-have skills: 3+ years of professional experience in Java backend development, strong proficiency in SQL, and a solid understanding of software design patterns.
• Soft skills: Clear communication, the ability to work effectively in a remote environment, and a proactive approach to solving technical debt.
• Nice-to-have skills: Experience with cloud infrastructure (AWS/GCP), familiarity with AI/ML integration, and experience with microservices architecture.

Q: How long should I spend preparing for the AI interview? A: Dedicate at least 1–2 weeks to brushing up on core Java concepts and SQL syntax. Focus on explaining your thought process clearly, as AI-based evaluations often analyze the logic behind your answers.

Q: What differentiates a successful candidate? A: Successful candidates don't just provide the "right" answer; they demonstrate a deep understanding of trade-offs. Always explain why you chose a specific design pattern or query approach over an alternative.

Q: Is this role fully remote? A: Yes, this position is remote. We prioritize candidates who have proven success in managing their own time and collaborating effectively through asynchronous communication tools.

• Practice SQL manually: Don't rely on IDE auto-complete. You should be comfortable writing standard SQL queries on a whiteboard or in a plain text editor.
• Focus on Design Principles: When asked about abstract classes vs. interfaces, focus on the "is-a" vs. "can-do" relationship. This demonstrates architectural maturity.
• Stay calm during AI rounds: Treat the AI interview as if you are explaining your thought process to a human colleague. Clarity and structure are your best assets.

The Software Engineer role at Sunking is a unique opportunity to apply your technical expertise to a mission that changes lives. By focusing on your core Java knowledge, refining your SQL proficiency, and practicing how you communicate your technical decisions, you will be well-positioned for success.

Prepare thoroughly, stay confident, and remember that our interview process is designed to find the best fit for our mission-driven culture. You have the skills to excel here—now it is time to demonstrate them. We look forward to seeing the impact you will make at Sunking.