60+ Senior Software Development Engineer Interview Questions and Answers

Level order traversal of a binary search tree from leaf to root.

• Perform a level order traversal of the binary search tree

• Start from the leaf nodes and move towards the root

• Print the nodes in a single line or print a new line for every level

Magic Tables in SQL Server are virtual tables used in triggers to access inserted and deleted rows during data modifications.

• Magic Tables are not actual tables; they are virtual tables created during the execution of triggers.

• The 'inserted' table contains new rows that are being added or updated.

• The 'deleted' table contains rows that are being removed or updated.

• Example: In a DELETE trigger, you can access the 'deleted' table to see which rows were removed.

• Example: In an UPDA...read more

Answers to common technical questions related to Spring Boot, microservices, programming concepts, and sample program implementation.

• Spring Boot annotations include @RestController, @Service, @Component, @Autowired, @RequestMapping, etc.

• Microservice architecture is a design approach where an application is composed of small, independent services that communicate over HTTP/REST or messaging protocols.

• Call by value passes a copy of the variable's value to a function, while call...read more

You can reset the identity column using DBCC Checkident command.

• Use DBCC Checkident command with RESEED option to reset the identity column.

• Specify the table name and the new identity value as parameters.

• For example, to insert a new identity of 100 in a table named 'MyTable', use: DBCC Checkident('MyTable', RESEED, 100);

Re-architected a failing ML system for predictive analytics in e-commerce, improving accuracy and performance significantly.

• Identified performance bottlenecks in the existing ML model, which was causing slow predictions.

• Replaced the original algorithm with a more efficient one, such as switching from a linear regression to a gradient boosting model.

• Implemented feature engineering to enhance model inputs, leading to a 20% increase in prediction accuracy.

• Utilized cloud-based so...read more

Split a singly linked list into odd and even indexed nodes

• Traverse the linked list and separate odd and even indexed nodes into two separate lists

• Reorder the nodes to have all odd index nodes at initial position followed by even index nodes

• Merge the two lists back together to form the final linked list

Use simple models for clarity and speed; complex models for accuracy and detail when necessary.

• Simple models are easier to understand and maintain, e.g., linear regression for predicting sales.

• Complex models capture intricate patterns, e.g., deep learning for image recognition tasks.

• Consider the problem domain: simple models suffice for well-defined problems, while complex models are needed for ambiguous ones.

• Evaluate the data availability: if data is limited, a simple model ...read more

To remove the nth node from the end of a linked list, we can use a two-pointer approach.

• Use two pointers, one moving n steps ahead of the other

• When the first pointer reaches the end, the second pointer will be at the nth node from the end

• Adjust the pointers to remove the nth node

CLR stands for Common Language Runtime. Delegates are type-safe function pointers. SOLID principles are design principles for software development. OOP pillars are Abstraction, Encapsulation, Inheritance, Polymorphism.

• CLR is the runtime environment in which .NET applications run.

• Delegates are type-safe function pointers that allow methods to be passed as parameters.

• SOLID principles are Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency ...read more

ACID properties are a set of properties that guarantee that database transactions are processed reliably.

• Atomicity ensures that either all operations in a transaction are completed successfully or none of them are.

• Consistency ensures that the database remains in a consistent state before and after the transaction.

• Isolation ensures that the concurrent execution of transactions results in a system state that would be obtained if transactions were executed serially.

• Durability en...read more

I applied causal inference techniques to optimize product features and improve user engagement through data-driven decisions.

• Utilized A/B testing to determine the impact of a new feature on user retention rates.

• Employed propensity score matching to compare user groups and assess the effectiveness of marketing campaigns.

• Analyzed time-series data to identify causal relationships between product updates and user activity spikes.

• Implemented regression discontinuity design to eval...read more

Building an app using SOLID principles ensures maintainability, scalability, and robustness in software design.

• S - Single Responsibility Principle: Each class should have one reason to change. For example, a User class should only handle user data.

• O - Open/Closed Principle: Classes should be open for extension but closed for modification. Use interfaces to allow new functionalities without altering existing code.

• L - Liskov Substitution Principle: Subtypes must be substitutabl...read more

DPDK core queue threads work by directly accessing NIC hardware queues for packet processing, bypassing the kernel for improved performance.

• DPDK core queue threads are used to handle packet processing in a multi-core environment.

• These threads directly access NIC hardware queues to receive and transmit packets.

• By bypassing the kernel, DPDK achieves lower latency and higher throughput for network applications.

• DPDK provides APIs for managing core queue threads and interacting wi...read more

Java 8 introduced several new features such as lambda expressions, streams, and functional interfaces.

• Lambda expressions allow for more concise code by enabling functional programming.

• Streams provide a way to work with collections in a more functional style, allowing for parallel processing and lazy evaluation.

• Functional interfaces are interfaces with a single abstract method, which can be implemented using lambda expressions.

• Other features include default methods in interfac...read more

Dependency injection is used to decouple components and improve testability, maintainability, and flexibility.

• Enables loose coupling between components

• Improves testability by allowing easy mocking and stubbing of dependencies

• Enhances maintainability by separating concerns and reducing code duplication

• Increases flexibility by enabling runtime configuration of dependencies

• Promotes modular and reusable code

• Facilitates easier unit testing and integration testing

Find duplicate elements from array

• Iterate through the array and use a hash set to keep track of seen elements

• If an element is already in the set, it is a duplicate

• Return the set of duplicate elements

Sort and remove duplicates from a list of numbers

• Convert the list of numbers to an array of strings

• Use a sorting algorithm to sort the array in ascending order

• Remove duplicates by iterating through the array and keeping track of unique elements

Design a validator and write a running code within 30 mins

• Define the validation rules and criteria

• Implement the validation logic using a programming language of choice

• Test the validator with different input data to ensure accuracy

Sort an arraylist with java stream and functional interfaces

• Use the sorted() method of Stream to sort the arraylist

• Pass a Comparator to the sorted() method to define the sorting order

• Use lambda expressions or method references to define the Comparator

• Collect the sorted stream back into an ArrayList using the collect() method

I utilize various tools for experiment tracking to ensure reproducibility and efficient collaboration in software development.

• MLflow: For managing the machine learning lifecycle, including experimentation, reproducibility, and deployment.

• Weights & Biases: Offers experiment tracking, dataset versioning, and collaboration features tailored for machine learning projects.

• TensorBoard: Primarily used for visualizing training metrics and model performance during deep learning experi...read more

An IOC Container in Spring Boot manages object creation and dependency injection for better modularity and testability.

• IOC stands for Inversion of Control, a design principle where the control of object creation is transferred to the container.

• Spring Boot uses the Spring Framework's IOC Container to manage beans and their dependencies.

• Beans are objects that are instantiated, assembled, and managed by the Spring IOC Container.

• Dependency Injection (DI) is a key feature of the I...read more

Systematic debugging involves identifying, isolating, and resolving issues in software through structured steps.

• Reproduce the issue: Ensure the bug can be consistently replicated to understand its nature.

• Check logs: Review application logs for error messages or unusual behavior that can provide clues.

• Use debugging tools: Utilize IDE debuggers or profilers to step through code and inspect variable states.

• Isolate the problem: Narrow down the code to the smallest section that pr...read more

I focus on modular design, scalability, and performance optimization to build robust systems that can grow with user demands.

• Start with requirements gathering: Understand user needs and system constraints.

• Use modular architecture: Break down the system into microservices for easier scaling and maintenance.

• Consider data storage: Choose between SQL and NoSQL based on data structure and access patterns; for example, use MongoDB for unstructured data.

• Implement caching strategies:...read more

I ensure code quality through best practices, automated testing, code reviews, and continuous integration.

• Implement coding standards and guidelines to maintain consistency across the codebase.

• Conduct regular code reviews to catch issues early and share knowledge among team members.

• Utilize automated testing frameworks (e.g., JUnit, pytest) to ensure functionality and catch regressions.

• Integrate continuous integration tools (e.g., Jenkins, GitHub Actions) to automate builds and...read more

I approach code reviews as collaborative opportunities to improve code quality and foster team learning.

• Establish clear guidelines: I ensure that the team has a shared understanding of coding standards and best practices.

• Use tools effectively: I leverage tools like GitHub or Bitbucket for inline comments, making it easier to discuss specific lines of code.

• Focus on constructive feedback: I aim to provide actionable suggestions rather than just pointing out issues. For example,...read more

Object-Oriented Programming (OOP) is a programming paradigm based on the concept of objects, which can contain data and methods.

• Encapsulation: Bundling data and methods that operate on the data within one unit (e.g., a class).

• Inheritance: Mechanism to create a new class using properties and methods of an existing class (e.g., a 'Dog' class inheriting from an 'Animal' class).

• Polymorphism: Ability to present the same interface for different underlying data types (e.g., a functi...read more

Convert an array of strings to a LinkedList

• Create a new LinkedList

• Iterate through the array and add each element to the LinkedList