1. What is Spring?
Spring is an open-source Java framework that provides comprehensive infrastructure support for developing Java applications. It simplifies the development of Java applications by providing features like dependency injection, inversion of control, aspect-oriented programming, and more.

2. What are the benefits of using Spring framework?
Some benefits of using Spring framework are:
– Loose coupling between components
– Ease of integration with other frameworks and libraries
– Efficient exception handling
– Simplified transaction management
– AOP (Aspect-oriented programming) capability
– Support for multiple databases

3. What is Dependency Injection?
Dependency Injection is a design pattern used in Spring to provide loose coupling between the classes. It allows the objects to be externally created and injected into other objects, rather than objects creating dependencies themselves.

4. Explain the concept of Inversion of Control (IOC) in Spring.
Inversion of Control (IOC) is a principle in Spring that states that externalizing the creation and management of objects is better for loose coupling. Instead of objects creating dependencies themselves, dependencies are provided or “injected” into the objects by an external entity, preferably through the use of interfaces.

5. What is the difference between BeanFactory and ApplicationContext in Spring?
BeanFactory is the basic container and the central interface to access the Spring container. It provides basic support for dependency injection. ApplicationContext is a sub-interface of BeanFactory and provides additional features like simplified integration with Spring AOP, event publication, and internationalization support.

6. What is Spring MVC?
Spring MVC is a module of the Spring framework that is used for building web applications based on the Model-View-Controller architectural pattern. It provides components like controllers, views, and a request lifecycle to handle user requests and generate responses.

7. What is the difference between singleton and prototype bean scopes in Spring?
Singleton scope means that only one instance of a bean is created for the entire application context. Prototype scope, on the other hand, creates a new instance of the bean whenever it is requested.

8. How can you achieve dependency injection in Spring?
Dependency Injection can be achieved in Spring through constructor injection, setter injection, or field injection using the @Autowired annotation.

9. What is Spring Security?
Spring Security is a powerful authentication and access-control framework provided by Spring. It enables secure authentication, authorization, and protection against common security threats in a Java application.

10. What is AOP in Spring?
AOP (Aspect-oriented Programming) is a technique used in Spring to separate cross-cutting concerns from business logic. It allows methods to be intercepted or weaved before, after, or around their execution. AOP in Spring is achieved using aspects, pointcuts, and advice.

11. What are the different types of dependency injections supported by Spring?
Spring supports three types of dependency injections:
– Constructor Injection: Dependencies are provided through a constructor.
– Setter Injection: Dependencies are provided through setter methods.
– Field Injection: Dependencies are directly injected into the fields using the @Autowired annotation.

12. What are the different modules in Spring framework?
Spring framework is divided into several modules, each responsible for specific functionalities. Some of the key modules are:
– Spring Core
– Spring MVC
– Spring Data
– Spring Security
– Spring AOP
– Spring Web Services

13. How does Spring support transaction management?
Spring supports transaction management through the use of the PlatformTransactionManager interface. It provides support for both programmatic and declarative transaction management. It also integrates with various transaction APIs, including JDBC, JTA, Hibernate, and JPA.

14. What is the use of @RequestMapping annotation in Spring MVC?
@RequestMapping is an annotation used in Spring MVC to define the request URL pattern that a controller method should handle. It maps the HTTP request to the appropriate controller method based on the URL pattern specified.

15. What is the purpose of the @Autowired annotation in Spring?
The @Autowired annotation is used to automatically wire dependencies into a Spring-managed bean. It can be applied to constructors, setter methods, and field declarations.

16. What is the difference between @Component, @Service, and @Repository annotations in Spring?
@Component is a generic stereotype annotation used for any Spring-managed component. @Service is a specialization of @Component used for service layer beans. @Repository is a specialization of @Component used for DAO (Data Access Object) classes.

17. What is the use of @Configuration annotation in Spring?
@Configuration annotation is used to indicate that a class defines Spring bean configuration. It is used in conjunction with @Bean annotation to define and configure Spring beans.

18. What are the different bean lifecycle callbacks in Spring?
The different bean lifecycle callbacks in Spring are:
– Initialization callbacks: @PostConstruct and InitializingBean interface
– Destruction callbacks: @PreDestroy and DisposableBean interface

19. How can you enable AspectJ support in Spring?
AspectJ support in Spring can be enabled by including the aspectjweaver.jar file in the classpath and configuration in the application context XML file.

20. What are the different bean scopes in Spring?
Spring supports several bean scopes, including singleton, prototype, request, session, and application. The default scope is singleton, which means one bean instance per Spring container.

1. What is the purpose of the @Qualifier Annotation in Spring?
The @Qualifier annotation is used to specify which bean should be autowired when multiple beans of the same type are present. It helps in resolving ambiguity during dependency injection.

2. How does Spring support Aspect-Oriented Programming (AOP)?
Spring supports AOP through the use of AspectJ annotations and proxy-based AOP. It allows you to separate cross-cutting concerns from the business logic by providing aspects that can be applied using annotations or XML-based configurations.

3. What is the @RequestMapping annotation used for in Spring MVC?
The @RequestMapping annotation is used to map a URL to a method in a Spring MVC controller. It allows you to define which HTTP methods are supported and specify request parameters or headers.

4. What is the difference between @Autowired and @Resource in Spring?
The @Autowired annotation is used for automatic wiring of dependencies by type. The @Resource annotation is used for automatic wiring by name. While @Autowired is a Spring-specific annotation, @Resource is a standard Java EE annotation.

5. How does Spring handle transaction management?
Spring provides declarative transaction management with the help of AOP. It allows you to define transactional boundaries using annotations or XML-based configurations. Spring manages the transaction lifecycle, including transaction demarcation, commit, and rollback.

6. What is the purpose of the @Transactional annotation in Spring?
The @Transactional annotation is used to mark a method or a class as transactional. It ensures that the method will be executed within a transactional context, allowing Spring to handle the transaction management aspects automatically.

7. Explain the concept of dependency injection in Spring.
Dependency injection is a design pattern in which an object’s dependencies are provided to it externally rather than constructing them internally. In Spring, it is facilitated using IOC (Inversion of Control) containers by wiring the dependencies either through constructor injection, setter injection, or field injection.

8. What is the difference between constructor injection and setter injection?
In constructor injection, dependencies are provided through the constructor at the time of object creation, ensuring that they are immutable. Setter injection, on the other hand, allows for optional dependencies and can be modified after object creation using setter methods.

9. What is the difference between BeanFactory and ApplicationContext in Spring?
BeanFactory is the basic interface for accessing Spring beans, providing the foundation for dependency injection and bean management. ApplicationContext extends BeanFactory and adds additional functionality like AOP, message resource handling, event publishing, and support for internationalization.

10. Explain the concept of Spring Security.
Spring Security is a powerful framework that provides authentication, authorization, and other security features for Java applications. It integrates seamlessly with Spring applications and allows you to secure URLs, method invocations, and implement various authentication mechanisms.

11. What is the purpose of the @ComponentScan annotation in Spring?
The @ComponentScan annotation is used to enable component scanning in Spring, allowing the framework to automatically discover and register beans that are annotated with relevant stereotype annotations such as @Component, @Service, or @Repository.

12. What is the purpose of the @Autowired annotation in Spring?
The @Autowired annotation is used to automatically wire dependencies in Spring. It allows Spring to handle the injection of dependencies without the need for explicit configuration.

13. What is the Spring Boot framework?
Spring Boot is a framework that simplifies the configuration and deployment of Spring applications. It provides opinionated defaults and auto-configuration, allowing developers to focus on writing business logic rather than dealing with boilerplate code.

14. Explain the concept of Spring Data JPA.
Spring Data JPA is a subproject of Spring that provides easy integration with JPA (Java Persistence API). It simplifies the development of database access code by providing repository interfaces with built-in CRUD operations and the ability to define custom query methods.

15. What is the purpose of the @Transactional annotation in Spring Data JPA?
The @Transactional annotation is used to define transactional boundaries for database operations in Spring Data JPA. It ensures that the operations will be executed within a transactional context, allowing Spring to handle aspects like transactional rollback and commit.

16. What is the difference between Hibernate and Spring Data JPA?
Hibernate is an ORM (Object-Relational Mapping) framework that provides persistence capabilities while Spring Data JPA is a subproject of Spring that simplifies the development of JPA-based repository interfaces. While Hibernate is a standalone ORM framework, Spring Data JPA integrates with Hibernate to provide easier database access.

17. How does Spring support caching?
Spring provides caching support through the use of @Cacheable, @CachePut, and @CacheEvict annotations. These annotations allow you to cache the results of expensive operations, reducing the overhead and improving performance.

18. What is the purpose of the @ExceptionHandler annotation in Spring MVC?
The @ExceptionHandler annotation is used to handle exceptions in Spring MVC applications. It allows you to define methods that will handle specific types of exceptions and return the appropriate response to the client.

19. What is the purpose of the @Scheduled annotation in Spring?
The @Scheduled annotation is used to schedule the execution of methods or tasks at specific intervals or times in Spring. It provides a simple way to implement background processing or perform regular tasks in a Spring application.

20. How does Spring support RESTful web services?
Spring provides support for building RESTful web services through the use of annotations like @RestController and @RequestMapping. It allows you to create endpoints that can handle HTTP methods, process request and response payloads, and return appropriate status codes.