OSB India Senior Software Engineer Interview Questions and Answers

Find k closest elements in an array

• Sort the array based on the absolute difference between each element and the target element

• Return the first k elements from the sorted array

Singleton pattern ensures a class has only one instance and provides a global point of access to it.

• Create a private static instance variable of the class.

• Make the constructor private to prevent instantiation from outside the class.

• Provide a static method to get the instance, creating it if necessary.

Pagination in SQL allows for displaying a subset of query results at a time.

• Use LIMIT and OFFSET clauses in SQL queries to implement pagination.

• LIMIT specifies the maximum number of rows to return.

• OFFSET specifies the number of rows to skip before starting to return rows.

Threads and tasks are both used in multiprocessing, but have different characteristics and use cases.

• Threads are lightweight processes within a single process, sharing memory space. They are managed by the operating system.

• Tasks are units of work that can be executed asynchronously. They are typically managed by a task scheduler.

• Threads are suitable for parallel processing and improving performance, while tasks are use...read more

ViewBag is used to pass data from controller to view, while TempData is used to pass data between controller actions.

• ViewBag is a dynamic property that allows you to pass data from controller to view

• TempData is a dictionary object that allows you to pass data between controller actions

• ViewBag is not type-safe and requires typecasting, while TempData is type-safe

• ViewBag data is lost if redirection occurs, while TempData

Abstract classes can have both abstract and non-abstract methods, while interfaces can only have abstract methods.

• Abstract classes can have constructors, fields, and non-abstract methods.

• Interfaces can only have abstract methods and constants.

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

REST API is a standard way of building web services, while Kafka is a distributed streaming platform for handling real-time data feeds.

• REST API is used for building web services that follow the REST architectural style

• Kafka is used for handling real-time data feeds and building real-time data pipelines

• REST API is synchronous, while Kafka is asynchronous and can handle high throughput and low latency data streams

Primary is used to define a primary bean when multiple beans of the same type are present, while Qualifier is used to specify which bean to autowire when multiple beans of the same type are present.

• Primary annotation is used to give a higher preference to a bean when multiple beans of the same type are present in the Spring application context.

• Qualifier annotation is used to specify which bean to autowire when multiple...read more

Fault tolerance in Microservices can be achieved through redundancy, graceful degradation, and circuit breakers.

• Implementing redundancy by having multiple instances of each microservice running to handle failures.

• Using graceful degradation to ensure that the system can still function even if certain microservices are unavailable.

• Utilizing circuit breakers to prevent cascading failures by temporarily stopping requests t

Implementing Spring Security involves configuring security settings in the Spring application.

• Add Spring Security dependency in pom.xml

• Configure security settings in SecurityConfig class

• Define user roles and permissions

• Use annotations like @EnableWebSecurity and @Secured

OAuth 2 is an authorization framework that allows a third-party application to obtain limited access to an HTTP service.

• OAuth 2 is used for delegated access, allowing a user to grant a third-party application access to their resources without sharing their credentials.

• It involves the use of access tokens, which are issued by the authorization server after the user authenticates and authorizes the application.

• OAuth 2 su...read more

Java uses automatic memory management through garbage collection to allocate and deallocate memory.

• Java uses garbage collection to automatically manage memory by deallocating objects that are no longer needed.

• The JVM has a heap where objects are allocated and garbage collection is performed to reclaim memory.

• Java provides the 'finalize()' method for objects to perform cleanup before they are garbage collected.

• Memory le...read more

Different types of garbage collection algorithms in software development.

• Mark and Sweep: Identifies and removes unreachable objects.

• Generational: Divides objects into different generations based on age.

• Parallel: Uses multiple threads to perform garbage collection concurrently.

• Incremental: Spreads garbage collection work over multiple cycles to reduce pause times.

Executors are a class that provides factory and utility methods for Executor, ExecutorService is an interface that represents an asynchronous execution service.

• Executors class provides factory and utility methods for Executor interface

• ExecutorService is an interface that represents an asynchronous execution service

• ExecutorService extends Executor interface

• ExecutorService provides methods to manage termination and produ...read more