2V0-72.22 Practice Questions

A.  

This is true because the Locale argument can be used to resolve the current locale that the client is using, based on the Accept-Language header or a cookie1.

B.  

This is true because the Principal argument can be used to access the currently authenticated user, if any1.

F.  

This is true because the HttpSession argument can be used to access the current session, if any1. Note that this argument is not required and will be null if a session does not exist.

This is true because Spring's JdbcTemplate class offers a variety of methods to execute SQL queries against a relational database. These include methods for executing SQL queries (query, queryForObject, queryForList, etc.), updates (update), and batch operations (batchUpdate).

B.  

This is true because the @DataJpaTest annotation enables auto-configuration of an embedded database if one is available on the classpath, such as H2, HSQLDB, or Derby. This allows the test to run with a temporary and isolated database that can be configured with test data.

D.  

This is true because the @DataJpaTest annotation provides a TestEntityManager bean that can be used to perform common JPA operations in the test. The TestEntityManager is an alternative to the standard EntityManager that provides some convenience methods and exception translation.

REST stands for Representational State Transfer, which is an architectural style for designing web services that adhere to certain principles. One of these principles is statelessness, which means that each request from a client to a server must contain all the information necessary to understand the request, and that no session state is maintained on the server side. Another principle is uniform interface, which means that clients and servers communicate using a standardized protocol, such as HTTP, and use its features, such as headers and status codes, to exchange information about the resources and their representations.

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.  

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.  

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.  

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()); }

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