How auto-configuration works in Spring Boot - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable Spring Boot auto-configuration in the main application class.

Spring Boot

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.[1](Application.class, args);
    }
}

Drag options to blanks, or click blank then click option'

Alaunch

Bstart

Cexecute

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method name other than 'run' causes the app not to start.

Forgetting to call any method to launch the app.

The SpringApplication.run() method starts the Spring Boot application and triggers auto-configuration.

2fill in blank

medium

Complete the annotation to enable Spring Boot's auto-configuration feature.

Spring Boot

@[1]
public class Application {}

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AEnableAutoConfiguration

BSpringBootApplication

CAutoConfigure

DConfiguration

Attempts:

3 left

💡 Hint

Common Mistakes

Using only @EnableAutoConfiguration misses component scanning.

Using @Configuration alone does not enable auto-configuration.

The @SpringBootApplication annotation includes auto-configuration, component scan, and configuration.

3fill in blank

hard

Fix the error in the code to correctly exclude a specific auto-configuration class.

Spring Boot

@SpringBootApplication(exclude = [1].class)
public class Application {}

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ADataSourceAutoConfiguration

BEnableAutoConfiguration

CSpringBootApplication

DAutoConfigure

Attempts:

3 left

💡 Hint

Common Mistakes

Using annotation names instead of class names causes errors.

Misspelling the class name.

To exclude an auto-configuration, specify the exact class name like DataSourceAutoConfiguration.class.

4fill in blank

hard

Fill both blanks to create a conditional auto-configuration class that activates only if a bean is missing.

Spring Boot

@Configuration
@ConditionalOnMissingBean([1].class)
public class [2]AutoConfiguration {}

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ADataSource

BJdbcTemplate

CCache

DSecurity

Attempts:

3 left

💡 Hint

Common Mistakes

Using unrelated bean types causes the condition to fail.

Mismatching class names and bean types.

This auto-configuration activates only if no DataSource bean exists, so it provides a default DataSourceAutoConfiguration.

5fill in blank

hard

Fill all three blanks to define a custom auto-configuration class with proper annotations and bean method.

Spring Boot

@Configuration
@ConditionalOnClass([1].class)
public class [2]AutoConfiguration {
    @Bean
    public [1] [3]() {
        return new [1]();
    }
}

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ARestTemplate

BMyService

CrestTemplate

DmyService

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for class and bean method.

Missing @Bean annotation.

This defines an auto-configuration that creates a RestTemplate bean if the class is on the classpath.