What is spring framework? Why Java programmer should use Spring framework?
Very common Spring interview question, Spring is a framework which helps Java programmer in development. Spring provides dependency Injection and IOC container, Spring MVC flow and several useful API for Java programmer.
What is default scope of bean in Spring framework ?
The default scope of a Spring bean is Singleton scope.
Does Spring singleton beans are thread-safe ?
No, Spring singleton beans are not thread-safe. Singleton doesn't mean bean would be thread-safe.
What is dependency Injection?
Dependency Injection is one of the design pattern, which allows injecting dependency on Object, instead of object resolving the dependency.
What is the front controller class of Spring MVC?
A front controller is defined as “a controller which handles all requests for a Web Application.” DispatcherServlet (actually a servlet) is the front controller in Spring MVC that intercepts every request and then dispatches/forwards requests to an appropriate controller.
When a web request is sent to a Spring MVC application, dispatcher servlet first receives the request. Then it organizes the different components configured in Spring’s web application context (e.g. actual request handler controller and view resolvers) or annotations present in the controller itself, all needed to handle the request.
Difference between <context:annotation-config> vs <context:component-scan>?
1) First big difference between both tags is that <context:annotation-config> is used to activate applied annotations in already registered beans in application context. Note that it simply does not matter whether bean was registered by which mechanism e.g. using <context:component-scan> or it was defined in application-context.xml file itself.
2) Second difference is driven from first difference itself. It registers the beans defined in config file into context + it also scans the annotations inside beans and activate them. So <context:component-scan> does what <context:annotation-config> does, but additionally it scan the packages and register the beans in application context.
Difference between @Component, @Controller, @Repository & @Service annotations?
1) The @Component annotation marks a java class as a bean so the component-scanning mechanism of spring can pick it up and pull it into the application context. To use this annotation, apply it over class as below:
@Component
public class EmployeeDAOImpl implements EmployeeDAO {
...
}
2) The @Repository annotation is a specialization of the @Component annotation with similar use and functionality. In addition to importing the DAOs into the DI container, it also makes the unchecked exceptions (thrown from DAO methods) eligible for translation into Spring DataAccessException.
3) The @Service annotation is also a specialization of the component annotation. It doesn’t currently provide any additional behavior over the @Component annotation, but it’s a good idea to use @Service over @Component in service-layer classes because it specifies intent better.
4) @Controller annotation marks a class as a Spring Web MVC controller. It too is a @Component specialization, so beans marked with it are automatically imported into the DI container. When you add the @Controller annotation to a class, you can use another annotation i.e. @RequestMapping; to map URLs to instance methods of a class.
What is view Resolver pattern ? how it work in Spring MVC?
Spring Framework Interview Question Answers | Spring MVC FAQView Resolver pattern is a J2EE pattern which allows a web application to dynamically choose it's view technology e.g. HTML, JSP, Tapestry, JSF, XSLT or any other view technology. In this pattern, View resolver holds mapping of different views, controller return name of the view, which is then passed to View Resolver for selecting an appropriate view. Spring MVC framework supplies inbuilt view resolver for selecting views.
What is Spring Security ?
Spring security is a project under spring framework umbrella, which provides support for security requirements of enterprise Java projects. Spring Security formerly known as aegis security provides out of box support for creating login screen, remember me cookie support, securing URL, authentication provider to authenticate the user from the database, LDAP and in memory, concurrent active session management support and much more. In order to use Spring security in a Spring MVC based project, you need to include spring-security.jar and configure it in application-Context-security.XML file, you can name it whatever you want, but make sure to supply this to ContextLoaderListener, which is responsible for creating Spring context and initializing dispatcher servlet.
How do you control concurrent Session on Java web application using Spring Security?
You can use Spring Security to control a number of active session in Java web application. Spring security framework provides this feature out of the box and when enabled , a user can only have one active session at a time.
What types of dependency injection is supported by Spring Framework? When do you use Setter and Constructor Injection, pros and cons?
There are 2 types of dependency injection supported by Spring, constructor based injection, and setter-based injection. Both types have their own advantages and disadvantages, you should use Constructor injection when object's dependencies are not optional and they must be initialized with their dependencies. Also use constructor injection if the order of initialization or dependency matters because in Setter based injection you cannot impose any order. Use setter injection when dependencies are optional.
How do Spring resolves view returned by ModelAndView class ?
Some Spring MVC questions are tricky e.g. Struts and Spring integration and can be only answered by experienced Java program with 2 to 4-year experience in Spring MVC framework.
What are different implementations of View interface you have used in Spring MVC?
ULBased View e.g. JSP , JSTLView,
Very common Spring interview question, Spring is a framework which helps Java programmer in development. Spring provides dependency Injection and IOC container, Spring MVC flow and several useful API for Java programmer.
What is default scope of bean in Spring framework ?
The default scope of a Spring bean is Singleton scope.
Does Spring singleton beans are thread-safe ?
No, Spring singleton beans are not thread-safe. Singleton doesn't mean bean would be thread-safe.
What is dependency Injection?
Dependency Injection is one of the design pattern, which allows injecting dependency on Object, instead of object resolving the dependency.
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| NetSuite Most Frequently Asked Spring MVC Latest Interview Questions Answers |
What is the front controller class of Spring MVC?
A front controller is defined as “a controller which handles all requests for a Web Application.” DispatcherServlet (actually a servlet) is the front controller in Spring MVC that intercepts every request and then dispatches/forwards requests to an appropriate controller.
When a web request is sent to a Spring MVC application, dispatcher servlet first receives the request. Then it organizes the different components configured in Spring’s web application context (e.g. actual request handler controller and view resolvers) or annotations present in the controller itself, all needed to handle the request.
Difference between <context:annotation-config> vs <context:component-scan>?
1) First big difference between both tags is that <context:annotation-config> is used to activate applied annotations in already registered beans in application context. Note that it simply does not matter whether bean was registered by which mechanism e.g. using <context:component-scan> or it was defined in application-context.xml file itself.
2) Second difference is driven from first difference itself. It registers the beans defined in config file into context + it also scans the annotations inside beans and activate them. So <context:component-scan> does what <context:annotation-config> does, but additionally it scan the packages and register the beans in application context.
Difference between @Component, @Controller, @Repository & @Service annotations?
1) The @Component annotation marks a java class as a bean so the component-scanning mechanism of spring can pick it up and pull it into the application context. To use this annotation, apply it over class as below:
@Component
public class EmployeeDAOImpl implements EmployeeDAO {
...
}
2) The @Repository annotation is a specialization of the @Component annotation with similar use and functionality. In addition to importing the DAOs into the DI container, it also makes the unchecked exceptions (thrown from DAO methods) eligible for translation into Spring DataAccessException.
3) The @Service annotation is also a specialization of the component annotation. It doesn’t currently provide any additional behavior over the @Component annotation, but it’s a good idea to use @Service over @Component in service-layer classes because it specifies intent better.
4) @Controller annotation marks a class as a Spring Web MVC controller. It too is a @Component specialization, so beans marked with it are automatically imported into the DI container. When you add the @Controller annotation to a class, you can use another annotation i.e. @RequestMapping; to map URLs to instance methods of a class.
What is view Resolver pattern ? how it work in Spring MVC?
Spring Framework Interview Question Answers | Spring MVC FAQView Resolver pattern is a J2EE pattern which allows a web application to dynamically choose it's view technology e.g. HTML, JSP, Tapestry, JSF, XSLT or any other view technology. In this pattern, View resolver holds mapping of different views, controller return name of the view, which is then passed to View Resolver for selecting an appropriate view. Spring MVC framework supplies inbuilt view resolver for selecting views.
What is Spring Security ?
Spring security is a project under spring framework umbrella, which provides support for security requirements of enterprise Java projects. Spring Security formerly known as aegis security provides out of box support for creating login screen, remember me cookie support, securing URL, authentication provider to authenticate the user from the database, LDAP and in memory, concurrent active session management support and much more. In order to use Spring security in a Spring MVC based project, you need to include spring-security.jar and configure it in application-Context-security.XML file, you can name it whatever you want, but make sure to supply this to ContextLoaderListener, which is responsible for creating Spring context and initializing dispatcher servlet.
How do you control concurrent Session on Java web application using Spring Security?
You can use Spring Security to control a number of active session in Java web application. Spring security framework provides this feature out of the box and when enabled , a user can only have one active session at a time.
What types of dependency injection is supported by Spring Framework? When do you use Setter and Constructor Injection, pros and cons?
There are 2 types of dependency injection supported by Spring, constructor based injection, and setter-based injection. Both types have their own advantages and disadvantages, you should use Constructor injection when object's dependencies are not optional and they must be initialized with their dependencies. Also use constructor injection if the order of initialization or dependency matters because in Setter based injection you cannot impose any order. Use setter injection when dependencies are optional.
How do Spring resolves view returned by ModelAndView class ?
Some Spring MVC questions are tricky e.g. Struts and Spring integration and can be only answered by experienced Java program with 2 to 4-year experience in Spring MVC framework.
What are different implementations of View interface you have used in Spring MVC?
ULBased View e.g. JSP , JSTLView,
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