4500+ Senior Software Engineer Interview Questions and Answers

Performance tuning in SQL optimizes query execution speed and resource usage for efficient data retrieval.

• Use indexes to speed up data retrieval. For example, adding an index on a frequently queried column can reduce search time.

• Analyze query execution plans to identify bottlenecks. Tools like SQL Server Management Studio provide insights into how queries are executed.

• Avoid SELECT *; specify only the columns needed to reduce data transfer and processing time.

• Use WHERE clauses...read more

Answering questions related to Spring Boot and core Java

• Spring Boot addons include Spring Security, Spring Data, and Spring Cloud

• Spring Boot is a framework for building standalone, production-grade Spring-based applications

• Ways of configuring a bean in Spring include XML configuration, Java-based configuration, and annotation-based configuration

• Core Java topics include OOP concepts, collections, multithreading, and exception handling

Implementing the lifecycle of a React component in a functional component

• Use the useEffect hook to replicate lifecycle methods like componentDidMount, componentDidUpdate, and componentWillUnmount

• Pass an empty array as the second argument to useEffect to mimic componentDidMount

• Pass a variable or state as the second argument to useEffect to mimic componentDidUpdate

• Return a cleanup function inside useEffect to mimic componentWillUnmount

CSS can be used to arrange elements in a row and column layout using flexbox or grid layout properties.

• Use display: flex; for a row layout and display: flex; flex-direction: column; for a column layout

• Use justify-content and align-items properties to align items in the main axis and cross axis respectively

• For grid layout, use display: grid; and grid-template-columns or grid-template-rows to define the layout

Various methods for creating an object in JavaScript include object literals, constructor functions, ES6 classes, and Object.create() method.

• Object literals: var obj = { key: value };

• Constructor functions: function ObjectName() { this.key = value; } var obj = new ObjectName();

• ES6 classes: class ClassName { constructor() { this.key = value; } } var obj = new ClassName();

• Object.create() method: var obj = Object.create(proto);

Redux is a predictable state container for JavaScript apps. Middlewares are functions that intercept actions before they reach the reducer.

• Redux follows a unidirectional data flow architecture.

• Middlewares in Redux are functions that can intercept, modify, or dispatch actions.

• Common use cases for middlewares include logging, asynchronous API calls, and handling side effects.

• Examples of popular Redux middlewares are Redux Thunk for async actions and Redux Logger for logging act...read more

Class-based components use ES6 classes and have lifecycle methods, while functional components are simpler and use functions.

• Class-based components use ES6 classes to create components, while functional components are created using functions.

• Class-based components have lifecycle methods like componentDidMount and componentDidUpdate, while functional components do not.

• Functional components are simpler and more lightweight compared to class-based components.

• With the introductio...read more

Hibernate is an ORM tool used to map Java objects to database tables.

• Hibernate simplifies database access by abstracting the JDBC API

• It provides a framework for mapping an object-oriented domain model to a relational database

• Hibernate supports lazy loading, caching, and transaction management

• It reduces the amount of boilerplate code needed for database operations

• Hibernate is widely used in enterprise Java applications

Interview questions for Senior Software Engineer

• 1) Largest Palindrom in a substring - use two pointers approach

• 2) Difference between wait and sleep in Thread - wait releases the lock, sleep doesn't

• 3) SQL join queries - inner, outer, left, right, self joins

• 4) Second largest employee salary SQL Query - use subquery or order by and limit

• 5) First level and second level cache in hibernate - first level is session specific, second level is application wide

• 6) Difference between get ...read more

Overview of caching, functional programming, transaction management, and security in Java and microservices.

• 1. Caching Mechanism: Use HashMap to store key-value pairs with methods to add, remove, and fetch values.

• 2. Functional Interface: Use Java 8's Stream API to filter even numbers from a list, e.g., list.stream().filter(n -> n % 2 == 0).collect(Collectors.toList()).

• 3. Caching Layer in Java 7: Implement a simple cache using HashMap with synchronized methods for thread safet...read more

Check server logs, review code, test endpoints, and verify database connections.

• Check server logs for error messages

• Review code for syntax errors or logical mistakes

• Test endpoints using tools like Postman or cURL

• Verify database connections and credentials

• Check for any recent changes or updates

• Consider scaling issues or server overload

• Consult with team members or experts if necessary

Optimizing query to fetch records from employee table based on city

• Create an index on the City column

• Use a WHERE clause with an index hint

• Use a stored procedure to cache the query results

• Use a materialized view to precompute the query results

My suggestion for implementation in Azure Data Factory v2 is to use the Mapping Data Flow feature.

• Utilize Mapping Data Flow for complex data transformations

• Take advantage of the visual interface to design and debug data flows

• Leverage the built-in data integration capabilities with other Azure services

• Use data flow parameters and expressions for dynamic transformations

• Monitor and optimize data flow performance using data flow debug and profiling

Spring is a Java framework for building web applications. Spring Boot is a tool that simplifies the process of creating Spring-based applications.

• Spring is a popular Java framework that provides a wide range of features for building web applications.

• Spring Boot is a tool that makes it easier to create Spring-based applications by providing a set of pre-configured defaults.

• The main difference between Spring and Spring Boot is that Spring requires a lot of configuration, while ...read more

Our code review process involves peer reviews and automated testing. We follow best practices and use manual testing for edge cases.

• Peer reviews are conducted for all code changes before merging into the main branch

• We use automated testing tools like Jest and Enzyme for unit and integration testing

• We follow best practices like writing clean and modular code, using meaningful variable names, and commenting where necessary

• Manual testing is used for edge cases and scenarios that...read more

Design classes for a bidding system with new bid notifications for users who have already bid.

• Create a Bid class with attributes like bidder, amount, timestamp, etc.

• Create a Notification class with attributes like message, recipient, timestamp, etc.

• Create a BiddingSystem class to manage bids and notifications.

• Implement a method in BiddingSystem to notify users who have already bid when a new bid is placed.

• Consider using Observer design pattern to notify users efficiently.

Dependency Injection is a design pattern used to remove hard-coded dependencies and make code more flexible and testable.

• Dependency Injection is implemented by injecting the required dependencies into a class rather than creating them within the class.

• This can be achieved through constructor injection, setter injection, or interface injection.

• For example, in Java, Spring Framework provides a powerful dependency injection mechanism through its @Autowired annotation.

• Dependency ...read more

Answers to interview questions for Senior Software Engineer

• 1. CASE is used to provide conditional logic in SQL queries, while DECODE is used to perform conditional value substitution.

• 2. Primary keys are used to uniquely identify each record in a database table.

• 3. Procedures and functions are both database objects that encapsulate a series of SQL statements, but functions return a value while procedures do not.

• 4. SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(sal...read more

Yes, we can create an index for a varchar column to improve query performance.

• Indexes can be created on varchar columns to speed up searches.

• Example: CREATE INDEX idx_name ON table_name (varchar_column);

• Consider the length of the varchar; longer lengths may impact performance.

• Partial indexes can be created for large varchar columns: CREATE INDEX idx_name ON table_name (varchar_column(10));

• Using indexes on varchar columns can improve SELECT query performance significantly.

Static variables and classes in OOP are used to store data that is shared among all instances of a class.

• Static variables are shared among all instances of a class and retain their value throughout the program's execution.

• Static classes cannot be instantiated and are used to group related static members together.

• Example: In a class representing a bank account, a static variable could be used to store the total number of accounts created.

• Example: A static class in a math libra...read more

Choosing between cluster or clusterless, Hive or U-SQL depends on project requirements and data processing needs.

• Clustered environments are suitable for large-scale data processing, while clusterless can be more cost-effective for smaller workloads.

• Hive is ideal for batch processing of large datasets using SQL-like queries, while U-SQL combines SQL with C# for more complex data manipulations.

• Example: Use Hive for ETL processes on Hadoop, and U-SQL for Azure Data Lake analytic...read more

Complex primary keys in Spring Data JPA can be created using @EmbeddedId or @IdClass annotations

• Use @EmbeddedId annotation to create a composite primary key using an embeddable class

• Use @IdClass annotation to create a composite primary key using a separate class for the key fields

• Implement equals() and hashCode() methods in the embeddable or separate key class for proper comparison and hashing

Count letter occurrences in a sentence and identify the maximum occurring letter.

• Use a dictionary to store letter counts. Example: 'a': 3, 'b': 2.

• Iterate through each character in the sentence, ignoring spaces and punctuation.

• Find the maximum count and corresponding letter using the dictionary.

• Consider case sensitivity: 'A' and 'a' can be counted separately or together.

The program prints a star pattern using asterisks and spaces.

• Use nested loops to iterate through rows and columns.

• Determine the number of asterisks and spaces to print in each row.

• Use conditional statements to decide when to print an asterisk or a space.

To scale a monolith architecture and improve response time, use horizontal scaling and implement caching.

• Implement horizontal scaling by adding more instances of the monolith application behind a load balancer

• Use a distributed cache to store frequently accessed data and reduce database queries

• Implement caching at different levels such as application-level caching, database query caching, and HTTP response caching

• Use a caching strategy based on the data access patterns and exp...read more

I verified the data by comparing the source and destination databases using SQL queries and automated scripts.

• Used SQL queries to check for data consistency between the source and destination databases

• Wrote automated scripts to compare records and identify any discrepancies

• Performed manual spot checks on a sample of transferred data to ensure accuracy

IRCTC reserves seats using a complex system of availability checks and booking processes.

• IRCTC uses a combination of real-time availability checks and booking processes to reserve seats.

• The system checks for availability of seats in real-time and reserves them for a short period of time while the booking process is completed.

• IRCTC uses a locking mechanism to ensure that the same seat is not booked by multiple users at the same time.

• The locking mechanism is based on a first-co...read more