Spring MVC Interview Questions

What is Spring MVC and what is its purpose?
Answer: Spring MVC is a framework used for building Java web applications. It provides a clear separation between the presentation layer, the controller, and the model. Its purpose is to simplify the development of web applications by providing a structured approach to handle requests and manage the flow of data between the different components of a web application.

What are the benefits of using Spring MVC?
Answer: The benefits of using Spring MVC include: - Easy integration with other Spring modules such as Spring Security, Spring Data, and Spring AOP - Support for RESTful web services - Flexible and customizable architecture - Provides a clear separation between different layers of an application - Good support for test-driven development

How does Spring MVC handle a web request?
Answer: When a web request is made to a Spring MVC application, it is first intercepted by the DispatcherServlet. The DispatcherServlet then delegates the request to a Controller. The Controller processes the request and returns a ModelAndView object, which contains the model data and the view name. The DispatcherServlet then uses the view name to resolve the view and render the response.

What is the role of the ModelAndView object in Spring MVC?
Answer: The ModelAndView object is a key component in the Spring MVC framework. It acts as a container for the model data and the view name. The ModelAndView object is returned by the Controller after processing the request. The DispatcherServlet uses the view name to resolve the view and render the response.

What is a Controller in Spring MVC?
Answer: A Controller in Spring MVC is a component that handles HTTP requests. It acts as an intermediary between the DispatcherServlet and the Model. The Controller processes the request, generates the model data, and returns a ModelAndView object to the DispatcherServlet.

How does Spring MVC handle different types of request?
Answer: Spring MVC supports different types of requests such as GET, POST, PUT, DELETE, etc. You can use the @RequestMapping annotation to map a specific request method to a controller method. For example, you can map a GET request to a controller method using the @GetMapping annotation.

How does Spring MVC support RESTful web services?
Answer: Spring MVC provides full support for building RESTful web services. You can use the @RestController annotation to create a RESTful Controller. The @RestController annotation is a combination of the @Controller and @ResponseBody annotations. It automatically converts the response from a Controller method into a JSON or XML response.

What is a ViewResolver in Spring MVC?
Answer: A ViewResolver in Spring MVC is a component that resolves the view name returned by a Controller into a View. The ViewResolver is responsible for selecting the appropriate view for rendering the response. You can configure different types of ViewResolvers such as InternalResourceViewResolver, XmlViewResolver, etc.

How can you validate user inputs in Spring MVC?
Answer: You can use the Bean Validation API to validate user inputs in Spring MVC. You can use the @Valid annotation to enable bean validation for a specific request parameter. If the validation fails, the framework automatically returns a response with an error message.

What is the difference between @Controller and @RestController annotations in Spring MVC?
Answer: The @Controller annotation is used to create a traditional MVC controller that handles HTTP requests and returns a ModelAndView object or a view name. On the other hand, the @RestController annotation is used to create a RESTful Controller that returns data in a serialized format, such as JSON or XML. The @RestController annotation is a combination of the @Controller and @ResponseBody annotations.

How can you handle exceptions in Spring MVC?
Answer: You can handle exceptions in Spring MVC by using the @ExceptionHandler annotation. The @ExceptionHandler annotation is used to define a method that will be called when a specific exception is thrown. You can also use the @ControllerAdvice annotation to define a global exception handler that will handle exceptions thrown by any Controller in your application.

What is the purpose of the ModelMap object in Spring MVC?
Answer: The ModelMap object is used to store model data in Spring MVC. It is an implementation of the Map interface and is used to pass data from the Controller to the View. The ModelMap is created by the DispatcherServlet and passed to the Controller and View.

How does Spring MVC handle form submissions?
Answer: Spring MVC handles form submissions by binding the request parameters to a JavaBean. You can use the @ModelAttribute annotation to bind a form submission to a JavaBean. The JavaBean can then be passed as a parameter to a Controller method and used to process the form submission.

What is the role of the ModelAttribute annotation in Spring MVC?
Answer: The @ModelAttribute annotation is used to bind a request parameter to a JavaBean. It can be used to bind form submissions or query parameters to a JavaBean. The JavaBean can then be used to process the request or to pass data to the View.

What is the purpose of the @Valid annotation in Spring MVC?
Answer: The @Valid annotation is used to enable bean validation in Spring MVC. It is used to validate user inputs in form submissions or query parameters. If the validation fails, the framework automatically returns a response with an error message.

How does Spring MVC support unit testing?
Answer: Spring MVC provides good support for unit testing. You can use the Spring Test framework to write unit tests for your Controllers, Views, and models. The Spring Test framework provides a mock implementation of the DispatcherServlet and makes it easy to write tests that simulate HTTP requests and test the behavior of your Controllers.

How does Spring MVC support AOP?
Answer: Spring MVC supports AOP by providing integration with the Spring AOP module. You can use AOP to add cross-cutting concerns, such as logging, security, and transaction management, to your application. AOP can be used to apply advice, such as before or after advice, to specific points in your code, such as method calls or exception handling.

What is the purpose of the @ResponseStatus annotation in Spring MVC?
Answer: The @ResponseStatus annotation is used to specify the HTTP status code that should be returned in the response. You can use the @ResponseStatus annotation on a Controller method to return a specific HTTP status code, such as 404 (Not Found) or 500 (Internal Server Error).

What is the difference between @RequestMapping and @GetMapping annotations in Spring MVC?
Answer: The @RequestMapping annotation is a generic annotation that is used to map HTTP requests to specific controller methods. The @GetMapping annotation is a specialized version of the @RequestMapping annotation that is used specifically to map GET requests. The @GetMapping annotation is more concise and provides better readability compared to the @RequestMapping annotation.

How can you pass data from a Controller to a View in Spring MVC?
Answer: You can pass data from a Controller to a View in Spring MVC by adding attributes to the ModelMap. The ModelMap is an implementation of the Map interface that is used to store model data. You can add data to the ModelMap in a Controller method and access the data in a View using EL expressions or JSTL tags.

How can you secure a Spring MVC application?
Answer: You can secure a Spring MVC application by using a variety of security measures, including authentication, authorization, and encryption. You can use the Spring Security framework to implement these security measures in your application. You can also use HTTPS to encrypt data in transit and prevent eavesdropping and tampering of data.

What is the purpose of the @PathVariable annotation in Spring MVC?
Answer: The @PathVariable annotation is used to bind a URL path variable to a Controller method parameter. You can use the @PathVariable annotation to extract data from the URL and pass it to a Controller method. The value of the @PathVariable annotation is automatically extracted from the URL and passed as a parameter to the Controller method.

How can you send a redirect response in Spring MVC?
Answer: You can send a redirect response in Spring MVC by using the "redirect:" prefix in the return value of a Controller method. When the "redirect:" prefix is used, the framework automatically sends a redirect response to the browser. The browser then sends a new request to the specified URL.

What is the difference between a redirect and a forward in Spring MVC?
Answer: A redirect is a two-step process where the browser sends a new request to the specified URL. A forward is a one-step process where the request is forwarded from one Controller to another Controller or from a Controller to a View. A forward does not send a new request to the browser and does not change the URL in the browser.

What is the purpose of the @InitBinder annotation in Spring MVC?
Answer: The @InitBinder annotation is used to customize data binding in Spring MVC. You can use the @InitBinder annotation to register custom editors that can be used to convert request parameters to custom objects. You can also use the @InitBinder annotation to validate user inputs and display error messages.

How does Spring MVC support content negotiation?
Answer: Spring MVC supports content negotiation by using the ContentNegotiationManager. The ContentNegotiationManager determines the format of the response based on the request's Accept header and the available formats that are supported by the application. You can configure the ContentNegotiationManager to support different formats, such as JSON, XML, or HTML.

What is the difference between Model and ModelMap in Spring MVC?
Answer: The Model is an interface that represents a container for model attributes, while the ModelMap is an implementation of the Model interface that is used to store model data. Both the Model and ModelMap are used to pass data from a Controller to a View. The ModelMap is a subclass of the HashMap class and provides additional methods for adding and accessing model data.

How does Spring MVC handle exceptions?
Answer: Spring MVC provides several ways to handle exceptions, including the @ExceptionHandler annotation, the SimpleMappingExceptionResolver, and the HandlerExceptionResolver interface. You can use the @ExceptionHandler annotation to handle specific exceptions in a Controller. You can use the SimpleMappingExceptionResolver to map exceptions to view names. You can also create a custom exception resolver by implementing the HandlerExceptionResolver interface.

What is the purpose of the @ModelAttribute annotation in Spring MVC?
Answer: The @ModelAttribute annotation is used to bind request parameters to a method parameter or a model attribute. You can use the @ModelAttribute annotation to bind data from the request to a method parameter or a model attribute before the method is called. The data can then be used in the method or be passed to the View.

What is the difference between @Controller and @RestController annotations in Spring MVC?
Answer: The @Controller annotation is used to mark a class as a Controller and handle HTTP requests, while the @RestController annotation is a specialized version of the @Controller annotation that is used to create RESTful web services. The @RestController annotation is used to return data in JSON or XML format, while the @Controller annotation returns data in HTML format.

How can you implement file upload in Spring MVC?
Answer: You can implement file upload in Spring MVC by using the MultipartFile interface. The MultipartFile interface represents a file that is uploaded in a multipart/form-data request. You can use the @RequestParam annotation to bind the uploaded file to a method parameter. You can then save the file to a specified location on the server or process it in any other way.

What is the purpose of the @ResponseBody annotation in Spring MVC?
Answer: The @ResponseBody annotation is used to indicate that the return value of a method should be bound to the HTTP response body. You can use the @ResponseBody annotation to return data in JSON or XML format, instead of returning a view name. The data is automatically serialized to the format specified by the request's Accept header or the configured ContentNegotiationManager.