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spring-framework-quiz.md

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Spring Framework

Q1. How filters are used in Spring Web?

  • Filters are called before a request hits the DispatcherServlet.They allow for interception-style, chained processing of web requests for security, timeouts, and other purposes.
  • Filters are used with a checksum algorithm that will filter invalid bytes out of a byte stream request body and allow for processing of HTTP requests from the DispatcherRequestServlet.
  • Filters are used with a checksum algorithm that will filter invalid bytes out of an octet stream a multipart upload and allow for chained processing of WebDispatcherServlet requests.
  • Filters are used to validate request parameters out of the byte stream request body and allow for processing of requests from the DispatcherRequestServlet.

Q2. How is a resource defined in the context of a REST service?

  • A resource is the actual String literal that composes a URI that is accessed on a RESTful web service.
  • It is an abstract concept that represents a typed object, data, relationships, and a set of methods that operate on it that is accessed via a URI.
  • A REST service has a pool of resources composed of allocations of memory that allow a request to be processed.
  • A resource for a REST service is an explicit allocation of a thread or CPU cycles to allow a request to be processed.

Q3. Which of these is a valid Advice annotation?

  • @AfterError
  • @AfterReturning
  • @AfterException
  • @AfterExecution

Q4. What does a ViewResolver do?

  • It supports internationalization of web applications by detecting a user's locale.
  • It generates a view by mapping a logical view name returned by a controller method to a view technology.
  • It creates a unique view determined by the uers's browser type,supporting cross-browser compatibility.
  • It maps custom parameters to SQL views in the database, allowing for dynamic content to be created in the response.

Q5. How are Spring Data repositories implemented by Spring at runtime?

  • Spring automatically generated code for you based on your YAML config that defined a MethodInterceptor chain that intercept calls to the instance and computed SQL on the fly.
  • A JDK proxy instance is created, which backs the repository interface, and a MethodInterceptor intercepts calls to the instance and routes as required.
  • The Spring JDK proxy creates a separate runtime process that acts as an intermediary between the database and the Web server, and intercepts calls to the instance and handles requests.
  • Spring automatically generated code for you based on your XML config files that define a SpringMethodAutoGeneration factory that intercepts calls to the instance and creates dynamic method that computer SQL on the fly.

Q6. What is SpEL and how is it used in Spring?

  • SpEL(Spring Expression Language) runs in the JVM and can act as a drop-in replacement for Groovy or other languages.
  • SpEL(Spring Expression Language) supports boolean and relational operators and regular expressions, and is used for querying a graph of objects at runtime.
  • SpEL(Spring Expression Language) allows you to build, configure,and execute tasks such as building artifacts and downloading object dependencies.
  • SpEL(Spring Expression Language) natively transpiles one JVM language to another, allowing for greater flexibility.

Q7. The process of linking aspects with other objects to create an advised object is called

  • dynamic chaining
  • banding
  • weaving
  • interleaving

Q8. How are JDK Dynamic proxies and CGLIB proxies used in Spring?

  • JDK Dynamic proxy can proxy only interface, so it is used if the target implements at least one interface. A CGLIB proxy can create a proxy by subclassing and is used if the target does not implement an interface.
  • Only JDK Dynamic proxies are used in the Spring Bean Lifecycle. CGLIB proxies are used only for integrating with other frameworks.
  • Only CGLIB proxies are used in the Spring Bean Lifecycle. JDK Dynamic proxies are used only for integrating with other frameworks.
  • JDK Dynamic proxy can only using an abstract class extended by a target. A CGLIB proxy can create a proxy through bytecode interweaving and is used if the target does not extend an abstract class.

Q9. Which of these is not a valid method on the JoinPoint interface?

  • getArgs()
  • getExceptions()
  • getSignature()
  • getTarget()

Q10. In what order do the @PostConstruct annotated method, the init-method parameter method on beans and the afterPropertiesSet() method execute?

  • 1. afterPropertiesSet() 2. init-method 3. @PostConstruct
  • 1. @PostConstruct 2. afterPropertiesSet() 3. init-method
  • 1. init-method 2. afterPropertiesSet() 3. @PostConstruct
  • You cannot use these methods together-you must choose only one.

Q11. What is the function of the @Transactional annotation at the class level?

  • It's a transaction attribute configured by spring.security.transactions.xml config file that uses Spring's transaction implementation and validation code.
  • It's a transaction must actively validate by the bytecode of a transaction using Spring's TransactionBytecodeValidator class. Default Transaction behavior rolls back on validation exception but commits on proper validation
  • It creates a proxy that implements the same interface(s) as the annotated class, allowing Spring to inject behaviors before, after, or around method calls into the object being proxied.
  • It's a transaction that must be actively validated by Spring's TransactionValidator class using Spring's transaction validation code. Default Transaction behavior rolls back on validation exception.

Q12. Which is a valid example of the output from this code (ignoring logging statements) ?

@SpringBootApplication
public class App {
     public static void main(String args[]) {
          SpringApplication.run(App.class, args);
          System.out.println("startup");
     }
}

public class Print implements InitializingBean {
     @Override
     public void afterPropertiesSet() throws Exception {
          System.out.println("init");
     }
}
  • Nothing will print
  • startup init
  • init
  • startup

Q13. Which println statement would you remove to stop this code throwing a null pointer exception?

@Component
public class Test implements InitializingBean {
     @Autowired
     ApplicationContext context;
     @Autowired
     static SimpleDateFormt formatter;

     @Override
     public void afterPropertiesSet() throws Exception {
          System.out.println(context.containsBean("formatter") + " ");
          System.out.println(context.getBean("formatter").getClass());
          System.out.println(formatter.getClass());
          System.out.println(context.getClass());
     }
}

@Configuration
class TestConfig {
     @Bean
     public SimpleDateFormat formatter() {
          return new SimpleDateFormat();
     }
}
  • formatter.getClass()
  • context.getClass()
  • context.getBean("formatter").getClass()
  • context.containsBean("formatter")

Q14. What is the root interface for accessing a Spring bean container?

  • SpringInitContainer
  • ResourceLoader
  • ApplicationEventPublisher
  • BeanFactory

Q15. Which annotation can be used within Spring Security to apply method level security?

  • @Secured
  • @RequiresRole
  • @RestrictedTo
  • @SecurePath

Q16. What is the result of calling the map controller method using the HTTP request GET localhost:8080/map?foo=foo&bar=bar ?

@RestController
public class SampleController {

     @RequestMapping("/map")
     public String map(@RequestParam("bar") String foo, @RequestParam("foo") String bar) {
          return bar + foo;
     }
}
  • An InvalidParameterNameMappingException is thrown at runtime.
  • barfoo
  • foobar
  • A status code of 400 Bad Request is returned.

Q17. What is the purpose of the @Lazy annotation and why would you use it?

  • It prevents a bean from being created and injected until you run a specific CLI command. It reduces complexity in the application.
  • It can be applied to a bean so that the bean is not persisted in the database. It reduces the number of database operations.
  • It can be applied to a bean so that the bean is not created and injected until it is needed. It can help speed up startup time for your application.
  • It prevents a bean from being created and injected until it receives a HTTP request to a callback hook. It reduces disk footprint.

Q18. What is dependency injection?

  • a method by which objects define dependencies they need as abstractions that allows the framework to instantiate and configure them in a central location at runtime.
  • a paradigm where dependent code is injected into the bytecode of a Java application on a remote server.
  • a way of injecting remote dependencies into a pre-packaged JAR file from the file system.
  • a way of injecting remote dependencies into a pre-packaged WAR file from the file system.

Q19. What is a RESTful web service?

  • Reactive Enterprise Status Transfer is a web service comprising a set of guidelines and technical constraints for web services that monitor and alert of a set of mission-critical resources.
  • Representational State Transfer an architectural style for creating web services that includes client-server architecture, statelessness, cacheability, a layered system, and a uniform interface.
  • Redundant Enumerated State Transfer is a web service that provides redundancy in the case of failure and outlines technical constraints for web services that have access to resources.
  • Reactive Enterprise State Transfer is a web service comprising a set of guidelines and technical constraints for web services y that have access to resources and are async in nature.

Q20. What happens when a class is annotated with the @Controller annotation?

  • A controller bean definition is defined in the servlet's WebApplicationContext. The class is marked as a web component, and you can map requests to controller methods.
  • A controller bean definition is defined in the Web Context, and Web Servlet is marked as a component that reads mapped controller requests from an XML config file.
  • A controller bean definition is defined in the Tomcat Context, and the Controller Servlet is marked as a web component that reads mapped controller requests from a YAML config file.
  • A controller bean definition is defined in the Servlet Context, and the Controller Servlet is marked as a component that reads mapped controller requests from an XML config file.

Q21. Which property can be used to change the port of a Spring application?

  • Port
  • spring.port
  • spring.settings.port
  • server.port

Q22. What is the purpose of the @ResponseBody annotation?

  • to validate the char array contained in a response to ensure that it is a valid character encoding
  • to generate a local byte stream from the body of a response that allows a request to be scanned for security risks
  • to indicate whether a handler method return value should be bound to the web response body in servlet environments
  • to ensure a ThreadLocal byte stream that allows a response to be encoded for reading directly into a socket stream

Q23. How are mocking frameworks such as Mockito used with Spring?

  • Mockito will spin up a mock web service hosted in a Docker container that can respond to HTTP requests to mock out third-party APIs.
  • Mockito can use annotations or factory methods to create mock objects that may be injected into tests in place of dependencies. The behavior of mocks can be explicitly configured.
  • Mockito will create mock users to repeatedly perform requests against your Spring application to test your app's ability to take load.
  • Mockito will spin up a mock web service hosted in a Docker container that can respond to RPC calls to mock out remote resources.

Q24. What is the name of the central servlet that dispatches requests to controllers?

  • DispatchingDelegatorServlet
  • DispatcherServlet
  • Router
  • FrontControllerServlet

Q25. What is the purpose of the Spring IoC (Inversion of Control) container?

  • It instantiates and configures objects, supplied at runtime, to classes that define them as a dependency.
  • It allows the front-end code to manage the ResponseBody objects provided by a back-end REST API.
  • It allows a database to define business objects via a shared schema at compile time.
  • It facilitates a remote server to configure a local application.

Q26. What is component scanning?

  • feature that scans packages for classes with specific annotations and, when found, creates their bean definitions within the IoC container
  • paradigm where bytecode is actively scanned to identify additional optimizations to inject into components in the application context
  • a method by which cloud repositories are scanned to identify components for injection into an IoC container
  • a method by which binary data in a database is searched to identify components for injection into the IoC container

Q27. What does @SpringBootApplication do?

  • This annotation takes the String literal passed into the annotation as a parameter and automatically generates all the code for your application as per the passed in template parameter.
  • This compound annotation applies the @Bootable, @Springify, and @StandardConfig annotations that launch a CLI tool after launching the Spring Boot WAR file that will guide you through a series of prompts to set up your app.
  • This annotation scans the provided spring-boot-config-construction.yaml file in your root directory and automatically generates all the code for your application as defined in the YAML file.

Q28. How does Spring Data facilitate queries against a datastore?

  • Queries are explicitly coded in repository implementations using the Spring Data CriteriaBuilder.
  • Query metadata is stored in the underlying datastore and retrieved at runtime per repository.
  • Queries are derived from the signatures of methods on a Spring Data repository that contain keywords in their name for constructing the query logic.
  • A spring-data-queries.xml file contains queries within entity tags that specify the query logic for each repository.

Q29. How does Spring generate bean names for classes annotated with @Component that do not specify a name?

  • It uses the short name of the class with the first letter in lowercase.
  • It uses the short name of the class.
  • It uses the short name of the class in uppercase.
  • It uses the canonical name of the class in lowercase.

Q30. What is the delegating filter proxy?

  • It's the servlet filter chain proxy that handles all requests to the route defined in spring.security.xml. All calls to the filter proxy are forwarded to the ErrorDispatcherServlet.
  • It's the servlet filter chain that handles requests to the route defined in spring.security.factories. All calls to the filter proxy y are forwarded to the ErrorServlet.
  • It's the servlet filter proxy delegating to a filter bean specified in web.xml. All calls to the filter proxy will be delegated to that servlet filter bean.
  • It's the web servlet daemon filter proxy that delegates to a bean specified in spring.security.factories. All calls to the filter proxy that do not contain a proper route will return an error.

Q31. What value does Spring Boot Actuator provide?

  • It helps monitor and manage a Spring Boot application by providing endpoints such as health checks, auditing, metrics gathering, and HTTP tracing.
  • It provides out-of-the-box functionality that integrates with third-party metrics platforms to automatically scale up and down the number of threads in threadpools.
  • It's a CLI that allows you to modify the configuration of a running Spring Boot application without the need for restarting or downtime.
  • It provides out-of-the-box functionality that integrates wiltr?third-party metrics platforms to automatically scale up and down the number of instances of the Spring Boot application.

Q32. What is the purpose of the @ContextConfiguration annotation in a JUnit Test?

  • It introspects the local machine and automatically provisions resources based on certain contextual configuration files.
  • It automatically generates comments for annotated classes on autowired dependencies to provide additional context about dependencies.
  • It defines metadata at the class-level to determine how to load or configure an ApplicationContext in Spring integration tests.
  • It automatically generates JavaDocs for annotated classes to provide additional context about the purpose of the class.

Q33. How are authentication and authorization different?

  • Authentication is the act of granting access to specific resources and functions based on config settings. Authorization is the act of introspecting a user's credentials to ensure they are not impersonating another user.
  • Authentication is the act of verifying certain resources and functions are actually valid. Authorization is the act of verifying a user's credentials have not expired.
  • Authentication is the act of verifying that certain resources and functions actually exist in the database. Authorization is the act of verifying a user's credentials to ensure they are valid.
  • Authentication is validating that users are who they claim to be. Authorization is granting access to specific resources and functions.

Q34. What is the purpose of the @RequestBody annotation?

  • to create a ThreadLocal byte stream that allows a request to be encoded for reading directly into a database
  • to automatically generate a ThreadLocal byte stream from the body of a request that allows a request to scanned for security risks
  • to indicate whether an annotated handler method parameter should be bound to the web request body, which is converted by an HttpMessageConverter
  • to automatically validate the characters contained in a request to ensure that they are a valid character encoding

Q35. What is the DispatcherServlet and what is its function?

  • The DispatcherServlet process daemon assigns a separate Web Servlet Container process to each HTTP request that comes into the web server.
  • It is a servlet that dispatches HTTP requests to registered handlers/controllers for processing.
  • The DispatcherServlet API assigns a separate Web Servlet Node process to each additional HTTP request that comes into the web server.
  • It is a servlet that dispatches an array of background daemon processes that allocate memory and CPU cycles to each request.

Q36. What is Spring Boot autoconfiguration?

  • It triggers a local automated review of configuration files such as web.xml and detects possible security issues or automatically resolves circular dependencies.
  • It triggers an automated review of configuration by a web-based agent that reviews your existing web.xml file and detects possible security issues.
  • It's an opinionated, intelligent method of introspecting an app to configure beans that are likely to be needed. This configuration can be overridden over time with manual configuration.
  • It provides plug-in functionality while editing your web.xml and other config files that will autocomplete common dependencies while typing.

Q37. Which are valid steps to take to enable JPA in Spring Boot?

  • Add an @EnableJpaRepositories annotation to your configuration class and create a Spring Data Repository.
  • Add an @EnableJpaEntities annotation to your configuration class, create a Spring Data YAML configuration file, and manually update the Spring XML config files to define your repository locations.
  • Add an @EnableDbFunctionality annotation to your configuration class, create a Spring Data XML configuration file, and manually update the Spring factories file to define your repositories.
  • Add an @InitJpaEntities annotation to your configuration class, create a Spring Data properties configuration file, and manually update the Spring startup parameters to define your repository locations.

Q38. What is a transaction in the context of Spring Data?

  • a version-controlled schema change that is applied to a database
  • a sequence of actions representing a single unit of work managed as a single operation that can be either committed or rolled back
  • an encoded message and response between various shards of a database
  • an exchange or interaction between various worker nodes in a multithreaded environment

Q39. Modularization of a concern that cuts across multiple classes is known as a(n)___.

  • multiclass
  • aspect
  • crosscut
  • sidecut

Q40. How do you inject a dependency into a Spring bean?

  • any of these answers
  • Annotate a Setter method with the @Autowired annotation.
  • Specify parameters in the constructor with an optional @Autowired annotation.
  • Use field injection.

Q41. Consider the properties file application.properties. How would you load the property my.property?

my.property=Test
  • A
@Prop("${my.property}")
private String val;
  • B
@GetVal("my.property")
private String val;
  • C
@GetProperty("${my.property}")
private String val;
  • D
@Value("${my.property}")
private String val;