Spring Boot Auto-Configuration and Starters 2

Question 1

Which annotation is placed on an auto-configuration class to ensure it only activates when a specific class is present on the classpath?

Accepted Answer

@ConditionalOnClass

Answer

@ConditionalOnClass causes Spring Boot to apply the configuration only when all specified classes are on the classpath.

Question 2

What happens when you add spring-boot-starter-data-jpa to your project without any database driver dependency?

Accepted Answer

The application fails to start with a 'Failed to determine a suitable driver class' error

Answer

Without a JDBC driver on the classpath, Spring Boot cannot auto-configure a DataSource and throws a startup failure.

Question 3

Which file inside a Spring Boot auto-configuration JAR registers auto-configuration classes for Spring Boot 3.x?

Accepted Answer

META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

Answer

Spring Boot 3.x uses META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports instead of the legacy spring.factories key.

Question 4

What is the purpose of the @AutoConfiguration annotation introduced in Spring Boot 2.7?

Accepted Answer

It marks a class as an auto-configuration candidate and sets ordering defaults

Answer

@AutoConfiguration is a specialization of @Configuration that signals the class is an auto-configuration, integrating naturally with the new imports file.

Question 5

Which property prefix is used to configure the embedded Tomcat server's port in a Spring Boot application?

Accepted Answer

server.port

Answer

Spring Boot's server auto-configuration reads server.port (default 8080) to bind the embedded Tomcat.

Spring Boot Practice Test

Spring Boot Practice Test

Spring Boot Auto-Configuration and Starters 2