2V0-72.22 Professional Develop VMware Spring Question and Answers

https://www.baeldung.com/transaction-configuration-with-jpa-and-spring

@Transactional(propagation = Propagation.SUPPORTS, readOnly = true)

https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/transaction/annotation/Transactional.html

The @Value annotation can be used to inject values from external sources into fields, constructor parameters, or method parameters. To inject a system property, the annotation can use either the ${…} placeholder syntax or the #{…} SpEL expression syntax. The former is simpler and more concise, while the latter is more powerful and flexible. Both syntaxes can access the systemProperties map, which contains all the system properties as key-value pairs.

The RestTemplate class is a Spring class that provides an easy way to communicate with RESTful web services from within an application. It offers several convenience methods for performing HTTP requests and handling HTTP responses, such as getForObject(), postForEntity(), exchange(), etc. It also supports automatic conversion of Java objects to and from JSON or XML using HttpMessageConverter instances.

A bean definition profile is a named logical grouping of bean definitions that can be activated or deactivated in different environments. For example, we can define different profiles for development, testing, and production environments. Spring provides the @Profile annotation to mark a bean definition or a configuration class as belonging to a specific profile. To activate a profile, we can use the spring.profiles.active property or the ConfigurableEnvironment.setActiveProfiles() method.

The @ActiveProfiles annotation is a class-level annotation that is used in conjunction with the Spring TestContext Framework to declare which profiles should be active when loading an ApplicationContext for an integration test. This annotation can be applied to any class annotated with @ContextConfiguration or a meta-annotation that is composed of @ContextConfiguration.

https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/aop/AfterReturningAdvice.html

Spring and Spring Boot provide various annotations and utilities to support testing of different layers of the application. To create an ApplicationContext for integration tests, we can use either @SpringBootTest or @SpringJUnitConfig annotations. The former is a specialized annotation that also provides additional features such as auto-configuration, web environment emulation, and test properties management. The latter is a general-purpose annotation that combines @ContextConfiguration and @ExtendWith(SpringExtension.class) annotations.

To perform slice testing, which focuses on testing a specific layer or feature of the application in isolation, we can use annotations such as @WebMvcTest, @DataJpaTest, @RestClientTest, etc. These annotations will only load the relevant beans for the tested slice and mock or stub the other dependencies.

Spring Security provides a fluent API for configuring web security based on URL patterns and request matchers. The authorizeRequests() method returns an expression that allows specifying access rules for different URLs using methods such as antMatchers(), regexMatchers(), mvcMatchers(), etc. The order of these rules matters, as they are evaluated from top to bottom. Therefore, it is recommended to put the most specific rules first and the least specific ones last.

A web slice test is a type of test in Spring Boot that focuses on testing only the web layer of an application, without starting a full server or requiring a real database. To isolate the web layer from other dependencies, such as services or repositories, mocks can be used to simulate their behavior and return predefined responses. To create and inject a mock for an existing bean in the application context, the @MockBean annotation can be used on a field or a parameter in the test class. This annotation will replace any existing bean of the same type with a mock created by Mockito.

A. It causes Spring Boot to enable auto-configuration by default.

This is true because the @SpringBootApplication annotation includes the @EnableAutoConfiguration annotation, which enables Spring Boot’s auto-configuration mechanism1. Auto-configuration attempts to automatically configure your Spring application based on the jar dependencies that you have added2.

B. Component scanning will start from the package of the class.

This is true because the @SpringBootApplication annotation includes the @ComponentScan annotation, which enables component scanning on the package where the application is located1. Component scanning allows Spring to automatically detect and register beans annotated with @Component, @Controller, @Service, @Repository, etc3.

The @Autowired annotation can be used to inject a dependency into a field, a constructor, or a setter method. However, if there are multiple beans of the same type in the application context, Spring will not be able to determine which one to inject by default. To resolve this ambiguity, we can use the @Qualifier annotation to specify the bean id of the desired dependency. Alternatively, we can use the bean id as the name of the field or the parameter of the setter method, and Spring will match it with the corresponding bean.

A. @Configuration This annotation indicates that the class has @Bean definition methods and may be processed by the Spring container to generate bean definitions and service requests for those beans at runtime. B. @ComponentScan This annotation configures component scanning directives for use with @Configuration classes. Provides support parallel with Spring XML's context:component-scan element.

The @Component annotation indicates that a class is a candidate for auto-detection by Spring and can be registered as a bean in the application context. However, to enable this feature, the Java configuration class must also have the @ComponentScan annotation, which tells Spring where to look for annotated components.

The JdbcTemplate class provides various methods to execute queries and manipulate the query results. Depending on the query and the expected result type, we can choose from the following three types of objects that can be returned from a JdbcTemplate query:

A. Generic Maps

This is true because the JdbcTemplate.queryForList method returns a List of Map objects, where each Map represents a row of the query result. The Map keys are the column names and the Map values are the column values1. For example:

List> results = jdbcTemplate.queryForList(“SELECT * FROM EMPLOYEE”); for (Map row : results) { System.out.println(row.get(“NAME”) + " " + row.get(“SALARY”)); }

B. Simple types (int, long, String, etc)

This is true because the JdbcTemplate.queryForObject method can return a single value of a simple type, such as int, long, String, etc. This method is useful for running queries that return a single row and a single column2. For example:

int count = jdbcTemplate.queryForObject(“SELECT COUNT(*) FROM EMPLOYEE”, Integer.class); System.out.println("Number of employees: " + count);

D. User defined types

This is true because the JdbcTemplate.query method can return a List of user defined types, such as custom classes or beans. This method takes a RowMapper as an argument, which is an interface that maps each row of the query result to an instance of the user defined type3. For example:

public class Employee { private String name; private int salary; // getters and setters }

public class EmployeeRowMapper implements RowMapper { @Override public Employee mapRow(ResultSet rs, int rowNum) throws SQLException { Employee employee = new Employee(); employee.setName(rs.getString(“NAME”)); employee.setSalary(rs.getInt(“SALARY”)); return employee; } }

List employees = jdbcTemplate.query(“SELECT * FROM EMPLOYEE”, new EmployeeRowMapper()); for (Employee employee : employees) { System.out.println(employee.getName() + " " + employee.getSalary()); }