Problem with the Getting Started documentation

[yousoumar]

The Getting Started documentation makes readers use the "default package", but as it's said on Developing with Spring Boot, it causes the following error when starting the project with mvn spring-boot:run:

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2023-08-30T13:46:09.258+02:00 ERROR 22934 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanDefinitionStoreException: Failed to read candidate component class: URL [jar:file:/Users/yousoumar/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/3.1.3/spring-boot-autoconfigure-3.1.3.jar!/org/springframework/boot/autoconfigure/r2dbc/ConnectionFactoryConfigurations$PoolConfiguration.class]
        at org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.scanCandidateComponents(ClassPathScanningCandidateComponentProvider.java:463) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.findCandidateComponents(ClassPathScanningCandidateComponentProvider.java:317) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.doScan(ClassPathBeanDefinitionScanner.java:276) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ComponentScanAnnotationParser.parse(ComponentScanAnnotationParser.java:128) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:289) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:243) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:196) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:164) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:415) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:287) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:344) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:115) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:771) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:589) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:734) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:436) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:312) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1295) ~[spring-boot-3.1.3.jar:3.1.3]
        at MyApplication.main(MyApplication.java:16) ~[classes/:na]
Caused by: java.lang.IllegalStateException: Could not evaluate condition on org.springframework.boot.autoconfigure.r2dbc.ConnectionFactoryConfigurations$PoolConfiguration due to io/r2dbc/spi/ValidationDepth not found. Make sure your own configuration does not rely on that class. This can also happen if you are @ComponentScanning a springframework package (e.g. if you put a @ComponentScan in the default package by mistake)
        at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:54) ~[spring-boot-autoconfigure-3.1.3.jar:3.1.3]
        at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:108) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:88) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:71) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.isConditionMatch(ClassPathScanningCandidateComponentProvider.java:518) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.isCandidateComponent(ClassPathScanningCandidateComponentProvider.java:501) ~[spring-context-6.0.11.jar:6.0.11]
        at org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.scanCandidateComponents(ClassPathScanningCandidateComponentProvider.java:436) ~[spring-context-6.0.11.jar:6.0.11]
        ... 20 common frames omitted
Caused by: java.lang.NoClassDefFoundError: io/r2dbc/spi/ValidationDepth
        at java.base/java.lang.Class.getDeclaredFields0(Native Method) ~[na:na]
        at java.base/java.lang.Class.privateGetDeclaredFields(Class.java:3397) ~[na:na]
        at java.base/java.lang.Class.getDeclaredField(Class.java:2705) ~[na:na]
        at org.springframework.boot.context.properties.bind.DefaultBindConstructorProvider$Constructors.isInnerClass(DefaultBindConstructorProvider.java:144) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.DefaultBindConstructorProvider$Constructors.getCandidateConstructors(DefaultBindConstructorProvider.java:134) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.DefaultBindConstructorProvider$Constructors.getConstructors(DefaultBindConstructorProvider.java:103) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.DefaultBindConstructorProvider.getBindConstructor(DefaultBindConstructorProvider.java:42) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.ValueObjectBinder$ValueObject.get(ValueObjectBinder.java:190) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.ValueObjectBinder.bind(ValueObjectBinder.java:67) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder.lambda$bindDataObject$5(Binder.java:482) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder$Context.withIncreasedDepth(Binder.java:596) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder$Context.withDataObject(Binder.java:582) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder.bindDataObject(Binder.java:480) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder.bindObject(Binder.java:419) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder.bind(Binder.java:348) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder.bind(Binder.java:337) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder.bind(Binder.java:267) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.context.properties.bind.Binder.bind(Binder.java:228) ~[spring-boot-3.1.3.jar:3.1.3]
        at org.springframework.boot.autoconfigure.r2dbc.ConnectionFactoryConfigurations$PooledConnectionFactoryCondition.getMatchOutcome(ConnectionFactoryConfigurations.java:148) ~[spring-boot-autoconfigure-3.1.3.jar:3.1.3]
        at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:47) ~[spring-boot-autoconfigure-3.1.3.jar:3.1.3]
        ... 26 common frames omitted
Caused by: java.lang.ClassNotFoundException: io.r2dbc.spi.ValidationDepth
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) ~[na:na]
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) ~[na:na]
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
        ... 46 common frames omitted

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  2.924 s
[INFO] Finished at: 2023-08-30T13:46:09+02:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:3.1.3:run (default-cli) on project project: Process terminated with exit code: 1 -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

[wilkinsona]

Duplicates #34513.