800+ Senior Software Developer Interview Questions and Answers

Spring Boot offers basic annotations like @Controller, @RestController, @Service, @Repository, @Component.

• @Controller - Used to mark a class as a Spring MVC controller.

• @RestController - Combination of @Controller and @ResponseBody, used to create RESTful web services.

• @Service - Used to mark a class as a service component in Spring.

• @Repository - Used to mark a class as a data access component in Spring.

• @Component - General-purpose stereotype annotation for any Spring-managed c...read more

React context is a built-in feature for passing data through the component tree, while React Redux is a library for managing global state in React applications.

• React context is used for passing data down the component tree without having to pass props manually at every level.

• React Redux is a library that provides a centralized store for managing global state in a React application.

• React context is built into React, while React Redux is a separate library that needs to be inst...read more

StringBuffer is synchronized and thread-safe, while StringBuilder is not synchronized and faster.

• StringBuffer is synchronized, making it thread-safe for use in multi-threaded environments.

• StringBuilder is not synchronized, making it faster but not thread-safe.

• Use StringBuffer when thread safety is needed, and StringBuilder for better performance in single-threaded scenarios.

Prototype chain in JavaScript is the mechanism by which objects inherit properties and methods from other objects.

• In JavaScript, each object has a private property which holds a link to another object called its prototype.

• If a property or method is not found on an object, JavaScript will look for it in the object's prototype, and so on up the chain.

• This allows for inheritance in JavaScript, where objects can inherit properties and methods from their prototypes.

The function returns a doubly linked list of all the nodes at each level of a given binary tree.

• Use a breadth-first search (BFS) algorithm to traverse the binary tree level by level.

• Create a doubly linked list for each level and append the nodes to it.

• Connect the doubly linked lists of each level to form the final result.

The answer provides regex patterns to extract specific information from a given text.

• Use the appropriate regex pattern to match the desired information

• Consider any variations or patterns in the text that may affect the regex

• Test the regex patterns with sample texts to ensure accuracy

To use a method in a different file in a Spring MVC project, you need to create a bean for the class containing the method and then inject it where needed.

• Create a bean for the class containing the method in the Spring configuration file

• Use @Autowired annotation to inject the bean where the method needs to be used

• Ensure the class containing the method is in the component scan path

Answers to questions related to microservice architecture, circuit breaker, service discovery, disadvantages of microservice, disadvantage of stream API, and default methods in functional interface.

• Microservice architecture allows for scalability, flexibility, and easier maintenance of complex systems.

• Circuit breaker is a design pattern used to prevent cascading failures in distributed systems.

• Service discovery is the process of automatically detecting and locating services i...read more

The @RestController annotation in Spring Boot is used to define a class as a RESTful controller.

• Used to create RESTful web services in Spring Boot

• Combines @Controller and @ResponseBody annotations

• Eliminates the need to annotate every method with @ResponseBody

• Returns data directly in the response body as JSON or XML

Hibernate provides several concurrency strategies like optimistic locking, pessimistic locking, and versioning.

• Optimistic locking: Allows multiple transactions to read a row simultaneously, but only one can update it at a time.

• Pessimistic locking: Locks the row for exclusive use by one transaction, preventing other transactions from accessing it.

• Versioning: Uses a version number to track changes to an entity, allowing Hibernate to detect and resolve conflicts.

There are 204 squares on a chessboard.

• The chessboard has 64 squares in total.

• Each square can be divided into smaller squares, such as 1x1, 2x2, 3x3, etc.

• The total number of squares can be calculated by adding the squares of all sizes together.

Proficient in Java, Python, and JavaScript.

• Java

• Python

• JavaScript

Questions related to Java concepts and frameworks

• Fail safe fail fast - used in concurrent programming to handle exceptions and ensure thread safety

• String is immutable to ensure thread safety and prevent unintended changes to the string

• String buffer vs String builder - both are used to manipulate strings, but string builder is faster and not thread-safe

• Executor framework - used for asynchronous task execution and thread pooling

• Lombok Transient Volatile Synchronized keyword Fin...read more

Override and virtual are keywords in C# used for method overriding and polymorphism.

• Override keyword is used to provide a new implementation for a method in a derived class that is already defined in a base class.

• Virtual keyword is used to allow a method to be overridden in a derived class.

• Override keyword is used in the derived class to indicate that a method overrides a base class method.

• Virtual keyword is used in the base class to indicate that a method can be overridden i...read more

CTE is a temporary result set that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement in SQL.

• CTEs help improve readability and maintainability of complex SQL queries.

• They can be recursive, allowing for hierarchical data querying.

• CTEs are defined using the WITH keyword followed by the CTE name and query.

• Example: WITH cte_name AS (SELECT * FROM table_name) SELECT * FROM cte_name;

Annotations used in Spring Boot projects with explanations

• 1. @RestController - Used to define a controller and automatically includes @ResponseBody in all methods.

• 2. @RequestMapping - Maps HTTP requests to handler methods of MVC and REST controllers.

• 3. @Autowired - Used for automatic dependency injection.

• 4. @Component - Indicates that a class is a Spring component.

• 5. @Service - Indicates that a class is a service component in the business layer.

• 6. @Repository - Indicates that...read more

Independent microservices communicate through APIs, messaging queues, or event-driven architecture.

• Use RESTful APIs for synchronous communication between microservices

• Implement messaging queues like RabbitMQ or Kafka for asynchronous communication

• Leverage event-driven architecture with tools like Apache Kafka or AWS SNS/SQS

• Consider gRPC for high-performance communication between microservices

Use efficient data structures and algorithms to handle large data sets.

• Use indexing and partitioning to break down data into manageable chunks.

• Implement caching and lazy loading to reduce memory usage.

• Use parallel processing and distributed computing to improve performance.

• Optimize database queries and use NoSQL databases for scalability.

• Consider using data compression and encryption for security and storage efficiency.

Functions return a value while stored procedures do not.

• Functions can be used in SQL statements while stored procedures cannot.

• Functions can be called from within stored procedures.

• Functions can be used in views while stored procedures cannot.

• Functions can have input parameters while stored procedures can have both input and output parameters.

Abstract class can have implementation while interface cannot.

• Abstract class can have constructors while interface cannot.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Abstract class can have non-abstract methods while interface can only have abstract methods.

• Abstract class can have instance variables while interface cannot.

• Example of abstract class: public abstract class Animal { public void eat() { System.out.println('Eating'); } }

• Ex...read more

Memory for a string in Java is allocated on the heap, with a reference stored on the stack.

• Strings in Java are immutable, so once created they cannot be changed.

• String objects are stored on the heap, while references to them are stored on the stack.

• String literals are stored in a special memory area called the String Pool.

• String objects can also be created using the 'new' keyword.

Method references provide a more concise way to refer to methods by name instead of using lambda expressions.

• Method references can make code more readable and maintainable by reducing boilerplate code.

• They can be used to refer to static methods, instance methods, and constructors.

• Example: list.forEach(System.out::println) is equivalent to list.forEach(item -> System.out.println(item)).

Debugging Python OOP code involves identifying and fixing errors in class definitions and method implementations.

• Check for syntax errors: Ensure all colons, parentheses, and indentation are correct.

• Verify class inheritance: Ensure the parent class is correctly referenced in the child class.

• Inspect method definitions: Ensure methods are defined with 'self' as the first parameter.

• Look for attribute initialization: Ensure all attributes are initialized in the __init__ method.

• Che...read more

Multithreading is the concurrent execution of multiple threads to achieve parallelism and improve performance.

• Multithreading allows multiple threads to run concurrently within a single process.

• It enables parallel execution of tasks, improving performance and responsiveness.

• Background worker is a component that simplifies multithreading by providing a dedicated thread for executing time-consuming tasks in the background.

• It allows the main thread to remain responsive and not ge...read more

String is immutable while StringBuilder is mutable.

• String is a sequence of characters that cannot be modified once created.

• StringBuilder is a dynamic object that can be modified and manipulated.

• String concatenation creates a new string object while StringBuilder modifies the existing object.

• String is thread-safe while StringBuilder is not.

• Use String for small strings and StringBuilder for large strings or frequent manipulations.

To create a file and append text, use file handling functions in the programming language.

• Open the file in append mode

• Write the text to the file

• Close the file

Types of hashmaps in Java include HashMap, LinkedHashMap, and TreeMap.

• HashMap: basic implementation, no order guaranteed

• LinkedHashMap: maintains insertion order

• TreeMap: sorted by natural order or custom comparator