1. What is Spring Boot?
Spring Boot is a framework for building standalone, production-grade Spring-based applications. It provides a fast and efficient way to create and deploy Spring applications.
2. What are the benefits of using Spring Boot?
Spring Boot provides several benefits, including:
- Reduced development and configuration time
- Embedded servers for easy deployment
- Improved reliability and performance
- Easy integration with other Spring projects
3. What is an auto-configured class in Spring Boot?
An auto-configured class is a class in Spring Boot that automatically configures a particular aspect of the application based on its classpath, properties, and other factors.
4. What is the difference between Spring and Spring Boot?
Spring is a framework for building Java applications, while Spring Boot is a framework for building production-ready Spring-based applications.
5. What is the difference between @Component and @Service annotations in Spring?
The @Component annotation is a generic stereotype for any Spring-managed component, while the @Service annotation is specifically used for service-layer beans.
6. How does Spring Boot handle exceptions?
Spring Boot provides a built-in mechanism for handling exceptions through the use of the @ExceptionHandler annotation.
7. What is the difference between @Value and @Autowired annotations in Spring?
The @Value annotation is used to inject a value from the application.properties file into a bean, while the @Autowired annotation is used to autowire a bean.
8. How can you access application properties in Spring Boot?
You can access application properties in Spring Boot using the @Value annotation, the Environment interface, or the ConfigurationProperties annotation.
9. What is the difference between @Primary and @Qualifier annotations in Spring?
The @Primary annotation is used to specify a primary bean, while the @Qualifier annotation is used to qualify a bean.
10. What is the difference between @Configuration and @ComponentScan annotations in Spring?
The @Configuration annotation is used to define a Spring configuration class, while the @ComponentScan annotation is used to enable component scanning in Spring.
11. What is a Spring Boot starter?
A Spring Boot starter is a set of dependencies and templates that are used to create a new Spring Boot application.
12. What is the purpose of the @SpringBootApplication annotation in Spring Boot?
The @SpringBootApplication annotation is used to enable component scanning, configuration, and other features in a Spring Boot application.
13. How does Spring Boot handle security?
Spring Boot provides several features for handling security, including built-in authentication and authorization, and support for security-related configurations.
14. How does Spring Boot handle database access?
Spring Boot provides several features for handling database access, including built-in support for JPA, support for JDBC, and support for NoSQL databases.
15. How does Spring Boot handle caching?
Spring Boot provides several features for handling caching, including built-in support for caching using EhCache, Hazelcast, Infinispan, and other caching providers. It also provides support for caching using the CacheManager interface, and for caching using the @Cacheable annotation.
16. How does Spring Boot handle data validation?
Spring Boot provides several features for handling data validation, including built-in support for JSR-303 Bean Validation, support for Hibernate Validator, and support for custom validators.
17. How does Spring Boot handle internationalization (i18n)?
Spring Boot provides several features for handling internationalization (i18n), including built-in support for ResourceBundleMessageSource, support for ReloadableResourceBundleMessageSource, and support for LocaleResolver.
18. How does Spring Boot handle logging?
Spring Boot provides several features for handling logging, including built-in support for Logback, support for Log4j2, and support for Java Util Logging.
19. How does Spring Boot handle testing?
Spring Boot provides several features for handling testing, including built-in support for JUnit, support for TestNG, and support for mock testing using Mockito and other mock testing frameworks.
20. How does Spring Boot handle web services?
Spring Boot provides several features for handling web services, including built-in support for RESTful web services using Spring MVC and Jackson, support for SOAP web services using Spring Web Services, and support for WebSockets.
21. What is the difference between @Repository and @Service annotations in Spring?
The @Repository annotation is used to define a data repository, while the @Service annotation is used to define a service layer bean.
22. How does Spring Boot handle email sending?
Spring Boot provides built-in support for sending emails using JavaMailSender, and support for sending emails using other email-sending libraries.
23. How does Spring Boot handle file uploads and downloads?
Spring Boot provides built-in support for handling file uploads and downloads using the MultipartFile interface, and support for handling file uploads and downloads using other file-handling libraries.
24. How does Spring Boot handle background tasks?
Spring Boot provides built-in support for executing background tasks using the @Async annotation, and support for executing background tasks using other task scheduling libraries.
25. What is the difference between @ResponseBody and @RestController annotations in Spring?
The @ResponseBody annotation is used to specify that the return value of a method should be written to the response body, while the @RestController annotation is used to create a RESTful web service.
26. How does Spring Boot handle security for RESTful web services?
Spring Boot provides built-in support for securing RESTful web services using Spring Security, and support for securing RESTful web services using other security libraries.
27. How does Spring Boot handle sessions?
Spring Boot provides built-in support for handling HTTP sessions using the HttpSession interface, and support for handling HTTP sessions using other session management libraries.
28. How does Spring Boot handle data access using JPA?
Spring Boot provides built-in support for data access using JPA through the use of the Spring Data JPA library.
29. How does Spring Boot handle data access using JDBC?
Spring Boot provides built-in support for data access using JDBC through the use of the Spring JDBC library. It provides several features for handling JDBC, including support for DataSource, JdbcTemplate, and JdbcOperations. It also provides support for transaction management using the @Transactional annotation and the PlatformTransactionManager interface.
30. How does Spring Boot handle data access using NoSQL databases?
Spring Boot provides built-in support for data access using NoSQL databases through the use of the Spring Data MongoDB, Spring Data Cassandra, and Spring Data Redis libraries. It also provides support for other NoSQL databases through the use of the Spring Data Commons library.
31. How does Spring Boot handle data access using XML and JSON?
Spring Boot provides built-in support for data access using XML and JSON through the use of the Jackson library. It provides several features for handling XML and JSON, including support for JAXB, JSON serialization and deserialization, and XML serialization and deserialization.
32. How does Spring Boot handle exception handling?
Spring Boot provides built-in support for exception handling through the use of the @ExceptionHandler and @ControllerAdvice annotations. It also provides support for handling exceptions using the ErrorController interface and the ErrorAttributes interface.
33. How does Spring Boot handle security for web applications?
Spring Boot provides built-in support for securing web applications using Spring Security, and support for securing web applications using other security libraries. It provides several features for handling security, including support for authentication and authorization, support for user management, and support for protecting against common security threats such as cross-site scripting (XSS) and cross-site request forgery (CSRF).
34. How does Spring Boot handle configuration management?
Spring Boot provides built-in support for configuration management through the use of the @Value and @ConfigurationProperties annotations, and support for configuration management using the ConfigurableApplicationContext interface. It also provides support for externalizing configuration using property files, YAML files, and other configuration sources.
35. How does Spring Boot handle monitoring and management?
Spring Boot provides built-in support for monitoring and management through the use of the Spring Boot Actuator library. It provides several features for monitoring and managing a Spring Boot application, including support for monitoring application health, support for viewing application metrics, and support for managing application configuration.
36. What is the difference between @Configuration and @Component annotations in Spring?
The @Configuration annotation is used to define a configuration class, while the @Component annotation is used to define a component class.
37. What is the difference between @Autowired and @Inject annotations in Spring?
The @Autowired and @Inject annotations are used to perform dependency injection in Spring. The @Autowired annotation is part of the Spring Framework, while the @Inject annotation is part of the Java EE specification.
38. What is the difference between @Qualifier and @Primary annotations in Spring?
The @Qualifier annotation is used to specify a specific implementation of a bean to be injected, while the @Primary annotation is used to specify a default implementation of a bean to be injected.
39. What is the difference between @Scope and @Lazy annotations in Spring?
The @Scope annotation is used to specify the scope of a bean, while the @Lazy annotation is used to specify that a bean should be lazily initialized.
40. What is the difference between @Import and @ImportResource annotations in Spring?
The @Import annotation is used to import configuration classes in Spring, while the @ImportResource annotation is used to import XML configuration files.
41. What is the difference between @RestController and @Controller annotations in Spring?
The @RestController annotation is used to define a RESTful web service controller in Spring, while the @Controller annotation is used to define a web service controller in Spring. The @RestController annotation is a combination of the @Controller and @ResponseBody annotations, which means that it returns the data directly in the response body, rather than returning a view.
42. What is the difference between @Bean and @Component annotations in Spring?
The @Bean annotation is used to define a bean in a configuration class, while the @Component annotation is used to define a component in a component class. The @Bean annotation is used in combination with the @Configuration annotation, while the @Component annotation is used in combination with the @ComponentScan annotation.
43. What is the difference between @Service and @Repository annotations in Spring?
The @Service annotation is used to define a business service in Spring, while the @Repository annotation is used to define a data repository in Spring. The @Service annotation is used to define services that are used by the application, while the @Repository annotation is used to define data access objects that are used to access the database.
44. What is the difference between a BeanPostProcessor and a BeanFactoryPostProcessor in Spring?
A BeanPostProcessor is used to post-process individual beans after they have been instantiated, while a BeanFactoryPostProcessor is used to post-process the entire bean factory before any beans have been instantiated.
45. What is the difference between an ApplicationListener and an ApplicationEvent in Spring?
An ApplicationListener is used to listen for ApplicationEvents in Spring, while an ApplicationEvent is a custom event that can be raised and listened to by ApplicationListeners.
46. What is the difference between a Spring Bean and a Spring Component?
A Spring Bean is a managed object in the Spring Framework, while a Spring Component is a class that is annotated with the @Component annotation and is eligible to be managed as a bean in the Spring Framework.
47. What is the difference between a Spring Boot Application and a Spring Application?
A Spring Boot Application is a pre-configured, stand-alone application that makes it easy to develop and run Spring applications, while a Spring Application is a general-purpose application that is built using the Spring Framework. Spring Boot provides many features and conveniences for developing Spring applications, including support for auto-configuration, embedded web servers, and pre-configured templates for common use cases.
48. What is transaction management in Spring?
Transaction management in Spring refers to the process of controlling the behavior of transactions in an application, including the start and end of transactions, the management of transaction boundaries, and the handling of transaction exceptions. Transaction management in Spring is performed by the transaction manager, which is responsible for managing transactions and ensuring that all changes made to the database within the scope of a transaction are either committed or rolled back.
49. What is transaction rollback in Spring?
Transaction rollback in Spring refers to the process of undoing all changes made to the database within the scope of a transaction, in case of a failure. A transaction can be rolled back if an exception occurs within the scope of the transaction, or if the transaction manager is instructed to do so explicitly.
50. What are the benefits of using transactions in Spring?
The benefits of using transactions in Spring include:
Data consistency and integrity: Transactions ensure that all changes made to the database within the scope of the transaction are either committed or rolled back so that the database remains in a consistent state.
Atomicity: Transactions are atomic, meaning that all operations either succeed or fail together.
Isolation: Transactions are isolated from each other, meaning that the changes made within one transaction do not affect other transactions.
Durability: Transactions are durable, meaning that once a transaction is committed, its changes persist even if the system fails.