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Spring Framework interview questions

Commands 

.\gradlew bootrun   --args='--server.port=8888'    to change the port number in the bootrun




Spring 

1. What is dependency injection

2. What is inversion of control

3. What is the role of IOC Container

4. Spring bean life cycle

5. What is ApplicationContext - IOC Conatiner, in addition it provide like AOP, internationalization, web application features

6. What is Beanfactory  - IOC conatiner, but only basic features (Memory constraint) 

7. How to define application context? using java @Configuration  or XML . AnnotationConfigApplicationContext  

8. for junit how to create the context configuration ? 

using @Runwith() and @ContextConfiguration 

9. What is the ComponentScan ?  @Component, find where the components are, @Componentscan using the basePackages to search in the package.

10. @SpringBootApplication ?  this will initaite the conponentscan within package or subpackages, if we need to explicitly provide we need to provide that 

11. @SpringBootTest 

12. @Component - something is an bean, managed by spring framework. @Autowired - find an matching dependency. @Component vs @Repository vs @Service, there are multiple layers, @Component is generic @Controller means MVC at web layer, @Repository something on the data layer, getting data from database. @Service used in the business layer, all the facade . @Repository - Spring translates the JDBC exception

13. What is the scope of bean, Singleton , Prototype , Session , Request

14 Singleton vs Prototype bean scope? Singleton is the default scope in bean.

15 Request vs Session Bean scope - only for web application context ? 

16. Are Spring bean threadsafe ? NO 

17. How is Spring singleton pattern vs gang of four singleton ? 

18. One instance per class loader vs one instance per application context ?  

19. different types of dependency injection - setter vs constructor injection ? what is the preference ? @Autowired on top of the properties or @Autowired on top of the constructor, Mandatory vs optional dependency ? 

20. NoUniqueBeanDefinitionException vs NoSuchBeanDefinitionException , NoSuchBeanDefinitionException    if the spring is not able to search any implementation then it will throw the error NoSuchBeanDefinitionException , that can also be the issue if that is on an different package (component scan definition) . TWO Components for the same bean -        NoUniqueBeanDefinitionException , Solution auto wiring by name      

21. what is @Primary - default 

22. @Qualifier ? 

23. What is CDI - Context and dependency injection ? Standard for javaEE similar to JPA (JSR-330)  @Inject vs @Autowired , @Named vs @Component, @Singleton per application context and supports the CDI Context. 

24. Spring 2.5 version support for annotation,Spring 3.0 - Java 5 languages,                        Spring 4.0  Java 8 support - Functional programming Spring 4.1 @RESTCONTROLLER for rest services and support for @JCache  , Spring 5.0  Functional web framework , and Support for Jigsaw and support for reactive programming using webflux, Support for kotlin.


25. What is Jigsaw and Java modulator ?

26. What are the different Spring modules ? 

27. Spring framework BOM in maven ?

28. MVC in Spring ?

29. Template Method Pattern ?

30.



 

 

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