Top Software Engineering Interview Questions (2023)

TeachingBee presents a comprehensive guide to software engineering interview questions for 2023. Dive into technical, behavioural, and culture fit questions for both freshers and experienced candidates.

Software engineering interviews aim to assess a wide range of technical and non-technical skills to hire the best developers, architects and managers. Here we look at some of the most common software engineering interview questions asked for both freshers and experienced candidates.

Technical Software Engineering Interview Questions for Freshers

1. Explain object oriented programming concepts like abstraction, encapsulation, inheritance and polymorphism.

Abstraction: Abstraction is the process of simplifying complex systems by breaking them into smaller, more manageable parts. In OOP, it involves defining classes with properties and methods to represent real-world entities.

Encapsulation: Encapsulation is the concept of hiding the internal details of an object and exposing only the necessary functionalities through methods and interfaces. It helps in data protection and maintaining a clean interface.

Inheritance: Inheritance allows a class (subclass or child class) to inherit properties and behaviors from another class (superclass or parent class). It promotes code reusability and hierarchy in class relationships.

Polymorphism: Polymorphism means the ability of different objects to respond to the same method or message in a way that is specific to their individual types. It enables flexibility and dynamic method invocation.

2. What are the differences between an abstract class and interface in Java? 

Abstract Class: An abstract class can have both abstract (unimplemented) and concrete (implemented) methods. It can also have instance variables. Subclasses must use the `extends` keyword to inherit from an abstract class.

Interface: An interface contains only method signatures (abstract methods) and constants (public, static, final variables). A class can implement multiple interfaces using the `implements` keyword.

3. Explain public, private, protected and default access modifiers in Java.

Public: Public members are accessible from any class and package.

-Private: Private members are only accessible within the same class.

Protected: Protected members are accessible within the same package and subclasses.

Default (Package-private): Members with no access modifier are accessible within the same package but not from outside.

Other Sample Technical Software Engineering Interview Questions for Freshers

4. What is function overloading and overriding in C++? Give examples.

5. Explain database normalization and different normal forms like 1NF, 2NF, 3NF.

6. What are primary keys and foreign keys? Give examples. 

7. Explain IP addressing and subnetting using CIDR notation.

8. What is deadlock? Explain livelock and how is it different from deadlock.

9. Write a program to reverse a string in place without using built-in reverse functions.

10. Explain how hash tables work and resolve collisions using chaining.

Advanced Software Engineering Interview Questions for Experienced

1. Design a highly scalable cloud-based mobile backend for a social media application.

– This design would involve multiple components like load balancers, databases, caching, microservices, and container orchestration (e.g., Kubernetes) for scalability. It would require considering data sharding, CDN integration, and security measures.

2. Design a search autocomplete system like Google search.

The system will have two key components – a datastore to store search prefixes and predictions, and a prediction service to serve autocomplete suggestions.

For the datastore, I will use a Trie data structure to store search prefixes mapped to suggestions and frequencies. The trie allows fast lookups and insertions to retrieve prefix matches. I will store the trie in an in-memory datastore like Redis for low latency.

The prediction service will be horizontally scaled with load balancing to handle large query volumes. It will expose APIs for applications to get autocomplete suggestions.

When a user types in a search prefix, the service will lookup the trie to find all stored prefixes matching the input. It will then sort these matches by usage frequency and return the top suggestions to display.

To build the prefix trie, I will use aggregated historical search data and continue to refine it based on incoming queries using machine learning. The ML model can identify correlations and patterns to provide better suggestions.

For reliability, the trie can be replicated across multiple nodes. The system can also cache popular queries in services like Memcached to reduce datastore load.

The search teams can continuously monitor system metrics like query latency, cache hit rate, datastore usage etc. and tune specific parameters like cache expiry, ML model retraining frequency etc. to improve autocomplete performance.

This architecture focused on fast in-memory datastores, intelligent ML models and horizontal scaling enables building a low-latency, accurate search autocomplete system.

3. Design an API rate limiter with throttling and distributed caching.

I would implement a token bucket algorithm to rate limit the API. Each API key will be allocated a bucket that refills with tokens at a pre-defined rate per second, up to a max burst size.

To perform a request, the calling service must acquire a token from its bucket. If no tokens available, the request will be throttled.

I will distribute the token buckets across multiple cache instances like Redis using consistent hashing of the API keys. This enables horizontal scaling of the rate limiter.

The caches will share token state using async multi-primary replication. If a cache fails, the key will map to a different cache using hashing.

A limit monitoring service will continuously poll usage across caches to identify clients approaching limits. We can have tiers like free, paid plans with higher limits.

API gateways can check the cache before forwarding requests to apply throttling.

To handle spikes in traffic, we can add a buffer of tokens that gets depleted before rejecting requests. The rate limiter is transparent to the calling services.

This architecture provides a scalable distributed rate limiter that can handle large traffic volumes and enforce limits fairly on API consumers.

Other Sample Advanced Software Engineering Interview Questions for Experienced

4. Design a ride sharing service like Uber focusing on scalability and reliability. 

5. Explain how you would improve performance of a poorly written application. 

6. Design a highly available and fault tolerant distributed key-value store.

7. Design an online stock brokerage platform supporting millions of users and high trading volumes per second. 

8. Explain how you would troubleshoot a production outage for a service with degraded performance.

9. Design a video streaming service using Content Distribution Network. Handle sharding, load balancing, caching etc. 

10. Explain how you would refactor a large legacy monolithic application into microservices.

Other Common Software Engineering Interview Questions  

1. How do you estimate tasks as part of agile development? Explain story points vs time estimation.

2. Explain test driven development and its benefits. 

3. What metrics would you track to measure software system performance? Explain their significance.

4. Explain unit testing vs integration testing vs system testing.

5. How do you ensure code quality in a continuous integration environment? 

6. Explain Scrum agile methodology – sprints, daily standups, retrospectives etc.

7. How do you protect user data privacy and build secure software? Explain common attacks. 

8. How do you ensure your software designs are scalable and extensible?  

9. Explain polymorphism as a key pillar of object oriented programming.

10. How do you handle technical debt and code refactoring in agile development?

Explore a wide range of interview questions covering diverse topics such as Object-Oriented Programming (OOP) and specific queries asked by prominent companies like IBM on Teaching Bee , under the “Interview Questions” section. You can access valuable insights to prepare for technical interviews, including concepts like abstraction, encapsulation, inheritance, polymorphism, and company-specific inquiries.

Behavioral/Culture Fit Software Engineering Interview Questions

1. Tell us about a challenging software project you worked on and how you overcame obstacles.

– I once worked on a complex e-commerce platform migration project. The challenge was migrating a massive database with millions of records without disrupting service. We faced data integrity issues, compatibility problems, and tight timelines. To overcome this, we meticulously planned the migration, conducted extensive testing, and implemented a phased approach. We also created rollback plans in case of failures. Clear communication and collaboration among the cross-functional team were crucial. Despite the challenges, the project was successful, with minimal downtime and zero data loss, showcasing our ability to tackle intricate tasks through meticulous planning and teamwork.

2. Explain a time you disagreed with team members on technical design and how it was resolved.

During a project, my team had differing opinions on the choice of a front-end framework. Some favored a popular but more complex option, while I advocated for a simpler, more efficient framework. To resolve this, we held a meeting to discuss pros and cons. We shared research and conducted a small proof-of-concept for both options. Ultimately, we decided to go with the simpler framework due to faster development time and better performance. The open dialogue and evidence-based approach helped us make an informed decision, fostering collaboration and ensuring the project’s success.

Other Sample Behavioral/Culture Fit Software Engineering Interview Questions

3. Tell us about a mistake you made during development and the lessons you learned.  

4. What qualities do you think are important for an engineering manager to be effective?

5. How do you mentor and train junior developers in your team? 

6. How do you stay updated with latest technology skills and industry trends?

7. Tell us about a time you faced multiple competing priorities and how you managed it.

8. What factors help build an effective and collaborative engineering culture?

9. How do you resolve conflicts and disagreements within an engineering team?

10. Why do you want to work for our company and what excites you about this role?

Other Resources

– To access additional study material related to DSA such as jump game 2 (DSA) and gain a deeper understanding of these topics, you can explore the available resources on the TeachingBee website. They likely provide a variety of articles, tutorials, and study materials to assist you in mastering DSA concepts and algorithms. These resources can be valuable for interview preparation and improving your problem-solving skills in computer science and programming.

This covers a wide range of technical and behavioral questions typically asked during software engineering interviews. Preparing relevant examples and stories to supplement the core concepts being tested is key to stand out.