Ribbon Communication Senior Research Associate Interview Questions and Answers

We are using Java 11 and Spring Boot 2.4.3 in our current project.

• Java 11 provides better performance and security features compared to previous versions.

• Spring Boot 2.4.3 offers improved support for Kotlin and GraalVM.

• We are also using Spring Data JPA for database access and Spring Security for authentication and authorization.

Singleton Design Pattern ensures only one instance of a class exists. No, we cannot create a clone of an object from singleton class.

• Singleton pattern restricts the instantiation of a class to one object.

• It is used when only one object is required to coordinate actions across the system.

• The instance is created only when it is requested for the first time.

• The constructor of the singleton class is private.

• Clone method is

Joins in SQL are used to combine data from two or more tables based on a related column.

• Joins are used to retrieve data from multiple tables in a single query

• Types of joins include inner join, left join, right join, and full outer join

• Join conditions are specified using the ON keyword and can include multiple conditions

• Aliases can be used to simplify the syntax of join queries

Triggers are database objects that automatically execute in response to certain events. Stored procedures are precompiled SQL statements.

• Triggers are used to enforce business rules or to audit changes to data.

• Stored procedures are used to encapsulate frequently used SQL statements for reuse and to improve performance.

• Triggers can be used to update related tables when a record is inserted, updated, or deleted.

• Stored pro...read more

Program to reverse sort keys in HashMap

• Create a List from the keySet() of the HashMap

• Sort the List in reverse order using Collections.sort()

• Iterate through the sorted List and add the keys to a new LinkedHashMap

• Return the LinkedHashMap

Maven is a build automation tool used primarily for Java projects. It manages dependencies and builds the project.

• Maven is based on the concept of POM (Project Object Model) which describes the project dependencies, build process, and other configurations.

• Maven has different cycles such as validate, compile, test, package, verify, install, and deploy.

• The validate cycle checks if the project is correct and all necessary...read more

Springboot annotations are used to simplify the development process and provide additional functionality.

• Annotations like @RestController and @RequestMapping are used to create RESTful web services.

• @Autowired is used for dependency injection.

• @Transactional is used to manage transactions.

• @Component is used to mark a class as a Spring component.

• @Value is used to inject values from properties files or environment variable...read more