20 Spring JDBC Interview Questions and Answers

Spring JDBC is a powerful tool for any Java developer. It simplifies the process of accessing and manipulating data in a database. When interviewing for a position that uses Spring JDBC, be prepared to answer questions about your experience and knowledge of the framework. This article discusses the most common Spring JDBC interview questions and how to answer them.

Spring JDBC Interview Questions and Answers

Here are 20 commonly asked Spring JDBC interview questions and answers to prepare you for your interview:

1. Can you explain what Spring JDBC is?

Spring JDBC is a framework that simplifies the process of working with databases in Java applications. It provides a template class for executing common database operations, and it also eliminates the need to write boilerplate code to handle exceptions and manage database connections.

2. What are some advantages of using the Spring framework for data access?

The Spring framework provides a number of advantages for data access, including the ability to use a consistent API for different types of data access technologies, the ability to abstract away the details of the underlying data access technology, and the ability to manage transactions declaratively.

3. How do you use PreparedStatementCreator to insert a record into the database?

You would use the PreparedStatementCreator to insert a record into the database by first creating a PreparedStatement and then using the PreparedStatement to execute an insert statement.

4. What’s the difference between RowCallbackHandler and ResultSetExtractor in Spring JDBC?

RowCallbackHandler is used when you want to process each row of a ResultSet one at a time. ResultSetExtractor is used when you want to process the entire ResultSet all at once.

5. How can you fetch the auto-generated keys from a table after inserting a new row?

You can use the JdbcTemplate’s update() method to execute an INSERT statement and return the auto-generated keys. You will need to pass in a PreparedStatementSetter to set the values for the insert, as well as a KeyHolder to hold the generated keys.

6. Why would you prefer one approach over another when executing SQL queries through JDBC?

There is no one-size-fits-all answer to this question, as the best approach to take when executing SQL queries through JDBC will vary depending on the specific situation. However, some factors that you may want to consider include the complexity of the query, the amount of data that needs to be retrieved, and the performance requirements.

7. How does Spring help with exception handling?

Spring provides a consistent approach to exception handling that can be applied across all layers of an application. This approach is useful for both development and production environments. In addition, Spring provides a convenient API for translating database-specific exceptions into more generic ones, making it easier to write code that is portable across different types of databases.

8. How do you retrieve data as objects instead of relational results in Spring JDBC?

In Spring JDBC, you can use the JdbcTemplate class to execute SQL queries and map the results to Java objects. The JdbcTemplate class provides several methods for mapping the results of a query to an object, including the queryForObject() and query() methods.

9. What is JdbcTemplate?

JdbcTemplate is a utility class that simplifies JDBC code, especially code that deals with opening and closing connections, executing statements, and handling resultsets. JdbcTemplate is thread-safe once configured, so multiple threads can access it concurrently without having to worry about data corruption or other thread-safety issues.

10. Is it possible to execute multiple statements simultaneously with Spring JDBC? If yes, then how?

Yes, it is possible to execute multiple statements simultaneously with Spring JDBC. This can be accomplished by using the JdbcTemplate.batchUpdate() method. This method takes an array of SQL statements and an array of parameters. The SQL statements will be executed in the order they are provided, and the parameters will be bound to the corresponding SQL statement.

11. How many ways are there to call stored procedures in Spring JDBC?

There are three ways to call stored procedures in Spring JDBC: using the SimpleJdbcCall class, using the JdbcTemplate.execute() method, or using the JdbcTemplate.call() method.

12. In which cases would you not want to use ORM tools like Hibernate and just go with plain old JDBC?

There are a few reasons you might not want to use an ORM tool like Hibernate. One reason is if you are working with a legacy database that is not compatible with Hibernate. Another reason is if you are working on a project where performance is critical and you need the extra control that JDBC gives you. Finally, if you are working on a project where the data model is very simple, then using an ORM tool might be overkill.

13. Is it possible to execute DDL statements with Spring JDBC?

Yes, it is possible to execute DDL statements with Spring JDBC. However, it is generally not recommended to do so, as DDL statements can potentially cause data loss. If you absolutely must execute a DDL statement, you can use the JdbcTemplate.execute() method.

14. What are some common problems that developers run into during bulk updates using JDBC?

One common problem is forgetting to set the auto-commit mode to false, which can lead to each update being committed individually and very slowly. Another is forgetting to close the connection, statement, and/or result set objects, which can lead to resource leaks. Finally, developers sometimes forget to properly handle SQLExceptions, which can cause the bulk update to fail entirely.

15. What is the purpose of the @Sql annotation?

The @Sql annotation is used to specify SQL queries that should be run when a test method is executed. This is useful for setting up test data or for running cleanup scripts after a test has been run.

16. How do you use NamedParameterJdbcTemplate to insert a new record into a table?

You would use the NamedParameterJdbcTemplate.update() method, passing in the SQL insert statement and a map of parameters. The keys in the map would be the names of the columns in the table, and the values would be the values to be inserted.

17. What are some best practices for writing efficient JDBC code?

Some best practices for writing efficient JDBC code include:

-Using PreparedStatements rather than Statement objects whenever possible
-Using connection pooling to minimize the number of times a connection needs to be opened and closed
-Batching SQL statements together to reduce the number of round trips to the database
-Using appropriate data types when storing data in the database (for example, using VARCHAR instead of TEXT for strings)
-Avoiding unnecessary database calls by caching data whenever possible

18. What do you understand about batch processing in Spring JDBC?

Batch processing in Spring JDBC refers to the ability to execute multiple SQL statements at once. This can be useful when you need to insert or update a large number of records in a database. Batch processing can help improve performance by reducing the number of round trips to the database.

19. What are some challenges that developers face while working with RDBMSs?

One of the main challenges that developers face when working with RDBMSs is that they are not always easy to use. This is because RDBMSs often require a lot of configuration and setup in order to work properly. Additionally, RDBMSs can be very slow and inefficient, which can make working with them a challenge.

20. What is your opinion on using microservices architecture with Spring Boot?

I think that microservices architecture is a great way to break up a large application into smaller, more manageable pieces. Spring Boot is a great framework for creating microservices, as it makes it easy to create stand-alone, production-grade Spring-based applications.