spring_interview_questions

Spring Framework Annotations

Sl.No Annotation Description
01. @Autowired Annotation @Autowired is used to inject object dependency implicitly for a constructor, field or method. This is known as “autowired by type” since the object to be injected is discovered by its type. The items declared @Autowired need not have to be public.
02. @Configurable Used on classes to inject properties of domain objects. Types whose properties are injected without being instantiated by Spring can be declared with @Configurable annotation.
03. @Qualifier It can be used to create more than one bean of the same type and wire only one of the types with a property. It provides greater control on the dependency injection process and can be used with @Autowired annotation.
04. @Required Used to mark class members that are mandatory. The Spring auto-configuration fails if a particular property specified with this annotation cannot be injected.
05. @ComponentScan Make Spring scan the package for the @Configuration clases.
06. @Configuration It is used on classes that define beans.
07. @Bean It indicates that a method produces a bean which will be mananged by the Spring container.
08. @Lazy Makes a @Bean or @Component to be initialized only if it is requested.
09. @Value It is used to inject values into a bean’s attribute from a property file. @Value annotation indicates a default value expression for the field or parameter.
10. @Resource Annotation used to inject an object that is already in the Appl­ication Context. It searches the instance by name. It also works on setter methods.
11. @Primary Annotation used when no name is provided telling Spring to inject an object of the annotated class first. Used along with @Comp­onent.
12. @Component Generic stereotype annotation used to tell Spring to create an instance of the object in the Appl­ication Context. It’s possible to define any name for the instance, the default is the class name as camel case.
13. @Contr­oller Stereotype annotation for presen­tation layer.
14. @Repos­itory Stereotype annotation for persis­tence layer.
15. @Service Stereotype annotation for service layer.

Spring-Boot Web Annotations

Sl.No Annotation Description
01. @SpringBootApplication This annotation is used to qualify the main class for a Spring Boot project. The class used with this annotation must be present in the base path. @SpringBootApplication scans for sub-packages by doing a component scan.
02. @EnableAutoConfiguration Based on class path settings, property settings, new beans are added by Spring Boot by using this annotation.
03. @Controller Allows detection of component classes in the class path automatically and register bean definitions for the classes automatically.
04. @RestController Used in controllers that will behave as RESTful resources. @RestController is a convenience annotation that combines @Controller and @ResponseBody.
05. @ResponseBody Makes Spring to convert the returned object to a response body. This is useful for classes exposed as RESTful resources.
06. @RequestMapping Used to map web requests to specific handler classes and methods, based on the URI.
07. @RequestParam This annotation is used to bind request parameters to a method parameter in your controller.
08. @PathVariable This annotations binds the placeholder from the URI to the method parameter and can be used when the URI is dynamically created or the value of the URI itself acts as a parameter.

Profile

Sl.No Annotation Description
01. spring.profiles.active Property to be set in appl­ica­tio­n.p­rop­ert­ies in order to tell Spring what profiles are active.
02. @Profile(“dev”) Annotation used to define which profile can execute the annotated method.

Aspect Annotations

Sl.No Annotation USE Description
01. @Aspect Type Declares a class to be an aspect.
02. @After Method Declares a method to be called after a pointcut completes.
03. @AfterReturning Method Declares a method to be called after a pointcut returns successfully.
04. @AfterThrowing Method Declares a method to be called after a pointcut throws an exception.
05. @Around Method Declares a method that will wrap the pointcut.
06. @Before Method Declares a method to be called before proceeding to the pointcut.
07. @DeclareParents Static Field Declares that matching types should be given new parents,that is, it introduces new functionality into matching types.
08. @Pointcut Method Declares an empty method as a pointcut placeholder method.

Spring-Boot Testing Annotations

Sl.No Annotation Description
01. @AfterTransaction Annotation used to identify which method needs to be invoked after a transaction is completed.
02. @BeforeTransaction Used to identify the method to be invoked before a transaction starts executing.
03. @ContextConfiguration Declares the annotated classes which will be used to load the context for the test. The location of the configuration file has to be povided to Spring.
04. @DirtiesContext This annotation indicates the test(s) modify or corrupt the SpringApplicationContext and that it should be closed. Hence, context is reloaded before the next test is executed.
05. @ExpectedException The test method is expected to throw a particular exception, else the test fails.
06. @WebAppConfiguration Used to create web version of the application context.
07. @Repeat Specifies the test method to be executed multiple times.
08. @Transactional Describes transaction attributes on a method or class.
09. @Rollback Indicates if the transaction of a test method must be rolled back after the execution of the test completed.
10. @Commit Indicates that the transaction of a test method must be committed after the execution of the test completed.
11. @Timed Indicates the time limit for the test method. If the test has not completed execution before the time expires, the test fails.
12. @TestPropertySource Annotation specifies the property sources for the test class.
13. @Sql Annotation declares a test class/method to run SQL scripts against a database.
Workflow and Tools
Sl.No Category Tool Description
01. Development Spring Tool Suite (STS) STS is an Eclipse-based development environment that can be used to develop Spring applications easily.
02. Development Eclipse IDE used to develop Java applications. It has a plugin for develping Spring applications. Useful when working simultaneously on Spring and non-Spring based apps.
03. Development IntelliJ IDEA Provides a smooth environment and user experience for developing Spring applications. Provides a comprehensive view of the project forspeedy navigation, error highlighting, plugins for numerous purposes, code completion.
04. Unit Testing JUnit JUnit is a regression Testing Framework used to implement unit testing in Java with an enhanced speed and quality.
05. Unit testing Mockito It is an open source mocking framework to create mock classes and interfaces providing realistic tests to predict the behaviour of the application.
06. Unit testing JaCoCo Provides support for code-coverage measurement and generates a detailed test report.
07. API Testing JMeter Apache’s JMeter is an open source testing tool which includes load, functional, regression and performance tests.
08. API Testing Postman Postman is a powerful tool used to test web services. It provides a feature to create test collections and can be used for API testing.
09. API Testing REST-Assured Makes API tesing in Java simple by providing behaviour driven development. It can integrate with any existing Java automation framework.
10. Monitoring spring-boot-actuators Enables monitoring and managing Spring boot application by shipping production ready featues like health, metrics, HTTP tracing etc.
11. Monitoring Micrometer Micrometer is an application-neutral facade or abstraction for reporting application metrics which integrates with many monitoring systems, e.g., Graphite, New Relic and Statsd. Micrometer integrates with the metrics endpoint of spring-boot-actuators.
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