Ensure that @Bean methods are only declared on @Configuration classes

Closes gh-16190

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/EndpointAutoConfigurationTests.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -334,6 +334,7 @@ public class EndpointAutoConfigurationTests {
 
 	}
 
+	@Configuration
 	static class DataSourceConfig {
 
 		@Bean

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/EndpointWebMvcManagementContextConfigurationTests.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -198,6 +198,7 @@ public class EndpointWebMvcManagementContextConfigurationTests {
 
 	}
 
+	@Configuration
 	static class EnvConfiguration {
 
 		@Bean
@@ -208,6 +209,7 @@ public class EndpointWebMvcManagementContextConfigurationTests {
 
 	}
 
+	@Configuration
 	static class MetricsConfiguration {
 
 		@Bean
@@ -217,6 +219,7 @@ public class EndpointWebMvcManagementContextConfigurationTests {
 
 	}
 
+	@Configuration
 	static class LoggersConfiguration {
 
 		@Bean
@@ -236,6 +239,7 @@ public class EndpointWebMvcManagementContextConfigurationTests {
 
 	}
 
+	@Configuration
 	static class LogFileConfiguration {
 
 		@Bean
@@ -245,6 +249,7 @@ public class EndpointWebMvcManagementContextConfigurationTests {
 
 	}
 
+	@Configuration
 	static class AuditEventsConfiguration {
 
 		@Bean
@@ -264,6 +269,7 @@ public class EndpointWebMvcManagementContextConfigurationTests {
 
 	}
 
+	@Configuration
 	static class HeapdumpConfiguration {
 
 		@Bean
@@ -273,6 +279,7 @@ public class EndpointWebMvcManagementContextConfigurationTests {
 
 	}
 
+	@Configuration
 	static class ShutdownConfiguration {
 
 		@Bean

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/HealthIndicatorAutoConfigurationTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -627,6 +627,7 @@ public class HealthIndicatorAutoConfigurationTests {
 
 	}
 
+	@Configuration
 	protected static class JestClientConfiguration {
 
 		@Bean

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/dao/PersistenceExceptionTranslationAutoConfiguration.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,6 +22,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.bind.RelaxedPropertyResolver;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.core.env.Environment;
 import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
 
@@ -33,6 +34,7 @@ import org.springframework.dao.annotation.PersistenceExceptionTranslationPostPro
  * @author Stephane Nicoll
  * @since 1.2.0
  */
+@Configuration
 @ConditionalOnClass(PersistenceExceptionTranslationPostProcessor.class)
 public class PersistenceExceptionTranslationAutoConfiguration {
 

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/hateoas/HypermediaHttpMessageConverterConfiguration.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@ import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.hateoas.mvc.TypeConstrainedMappingJackson2HttpMessageConverter;
 import org.springframework.http.MediaType;
 import org.springframework.http.converter.AbstractHttpMessageConverter;
@@ -41,6 +42,7 @@ import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandl
  *
  * @author Andy Wilkinson
  */
+@Configuration
 public class HypermediaHttpMessageConverterConfiguration {
 
 	@Bean

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.jdbc.DatabaseDriver;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 
 /**
  * Actual DataSource configurations imported by {@link DataSourceAutoConfiguration}.
@@ -45,6 +46,7 @@ abstract class DataSourceConfiguration {
 	/**
 	 * Tomcat Pool DataSource configuration.
 	 */
+	@Configuration
 	@ConditionalOnClass(org.apache.tomcat.jdbc.pool.DataSource.class)
 	@ConditionalOnMissingBean(DataSource.class)
 	@ConditionalOnProperty(name = "spring.datasource.type", havingValue = "org.apache.tomcat.jdbc.pool.DataSource", matchIfMissing = true)
@@ -71,6 +73,7 @@ abstract class DataSourceConfiguration {
 	/**
 	 * Hikari DataSource configuration.
 	 */
+	@Configuration
 	@ConditionalOnClass(HikariDataSource.class)
 	@ConditionalOnMissingBean(DataSource.class)
 	@ConditionalOnProperty(name = "spring.datasource.type", havingValue = "com.zaxxer.hikari.HikariDataSource", matchIfMissing = true)
@@ -89,6 +92,7 @@ abstract class DataSourceConfiguration {
 	 *
 	 * @deprecated as of 1.5 in favor of DBCP2
 	 */
+	@Configuration
 	@ConditionalOnClass(org.apache.commons.dbcp.BasicDataSource.class)
 	@ConditionalOnMissingBean(DataSource.class)
 	@ConditionalOnProperty(name = "spring.datasource.type", havingValue = "org.apache.commons.dbcp.BasicDataSource", matchIfMissing = true)
@@ -116,6 +120,7 @@ abstract class DataSourceConfiguration {
 	/**
 	 * DBCP DataSource configuration.
 	 */
+	@Configuration
 	@ConditionalOnClass(org.apache.commons.dbcp2.BasicDataSource.class)
 	@ConditionalOnMissingBean(DataSource.class)
 	@ConditionalOnProperty(name = "spring.datasource.type", havingValue = "org.apache.commons.dbcp2.BasicDataSource", matchIfMissing = true)
@@ -134,6 +139,7 @@ abstract class DataSourceConfiguration {
 	/**
 	 * Generic DataSource configuration.
 	 */
+	@Configuration
 	@ConditionalOnMissingBean(DataSource.class)
 	@ConditionalOnProperty(name = "spring.datasource.type")
 	static class Generic {

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jdbc/XADataSourceAutoConfiguration.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,6 +34,7 @@ import org.springframework.boot.context.properties.EnableConfigurationProperties
 import org.springframework.boot.jdbc.DatabaseDriver;
 import org.springframework.boot.jta.XADataSourceWrapper;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -46,6 +47,7 @@ import org.springframework.util.StringUtils;
  * @author Josh Long
  * @since 1.2.0
  */
+@Configuration
 @AutoConfigureBefore(DataSourceAutoConfiguration.class)
 @EnableConfigurationProperties(DataSourceProperties.class)
 @ConditionalOnClass({ DataSource.class, TransactionManager.class,

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/batch/BatchAutoConfigurationTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -371,6 +371,7 @@ public class BatchAutoConfigurationTests {
 	}
 
 	@EnableBatchProcessing
+	@Configuration
 	protected static class NamedJobConfigurationWithRegisteredJob {
 
 		@Autowired
@@ -413,6 +414,7 @@ public class BatchAutoConfigurationTests {
 	}
 
 	@EnableBatchProcessing
+	@Configuration
 	protected static class NamedJobConfigurationWithLocalJob {
 
 		@Autowired
@@ -444,6 +446,7 @@ public class BatchAutoConfigurationTests {
 
 	}
 
+	@Configuration
 	@EnableBatchProcessing
 	protected static class JobConfiguration {
 

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/condition/ConditionalOnPropertyTests.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -434,6 +434,7 @@ public class ConditionalOnPropertyTests {
 
 	}
 
+	@Configuration
 	@ConditionalOnMyFeature
 	protected static class MetaAnnotation {
 
@@ -444,6 +445,7 @@ public class ConditionalOnPropertyTests {
 
 	}
 
+	@Configuration
 	@ConditionalOnMyFeature
 	@ConditionalOnProperty(prefix = "my.other.feature", name = "enabled", havingValue = "true", matchIfMissing = false)
 	protected static class MetaAnnotationAndDirectAnnotation {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jdbc/JndiDataSourceAutoConfigurationTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,7 @@ import org.springframework.boot.autoconfigure.jndi.TestableInitialContextFactory
 import org.springframework.boot.test.util.EnvironmentTestUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.jmx.export.MBeanExporter;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -167,7 +168,8 @@ public class JndiDataSourceAutoConfigurationTests {
 		TestableInitialContextFactory.bind(name, dataSource);
 	}
 
-	private static class MBeanExporterConfiguration {
+	@Configuration
+	static class MBeanExporterConfiguration {
 
 		@Bean
 		MBeanExporter mbeanExporter() {
@@ -176,7 +178,8 @@ public class JndiDataSourceAutoConfigurationTests {
 
 	}
 
-	private static class AnotherMBeanExporterConfiguration {
+	@Configuration
+	static class AnotherMBeanExporterConfiguration {
 
 		@Bean
 		MBeanExporter anotherMbeanExporter() {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/kafka/KafkaAutoConfigurationIntegrationTests.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@ import org.junit.Test;
 import org.springframework.boot.test.util.EnvironmentTestUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.kafka.annotation.KafkaListener;
 import org.springframework.kafka.core.KafkaTemplate;
 import org.springframework.kafka.support.KafkaHeaders;
@@ -98,6 +99,7 @@ public class KafkaAutoConfigurationIntegrationTests {
 		return File.separatorChar == '\\';
 	}
 
+	@Configuration
 	public static class KafkaConfig {
 
 		@Bean

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/security/oauth2/resource/ResourceServerTokenServicesConfigurationTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -324,6 +324,7 @@ public class ResourceServerTokenServicesConfigurationTests {
 
 	}
 
+	@Configuration
 	@Import({ OAuth2RestOperationsConfiguration.class })
 	protected static class ResourceNoClientConfiguration extends ResourceConfiguration {
 
@@ -351,6 +352,7 @@ public class ResourceServerTokenServicesConfigurationTests {
 
 	}
 
+	@Configuration
 	@Import({ FacebookAutoConfiguration.class, SocialWebAutoConfiguration.class })
 	protected static class SocialResourceConfiguration extends ResourceConfiguration {
 

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/MultipartAutoConfigurationTests.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -373,6 +373,7 @@ public class MultipartAutoConfigurationTests {
 
 	}
 
+	@Configuration
 	public static class ContainerWithCustomMultipartResolver {
 
 		@Bean
@@ -382,6 +383,7 @@ public class MultipartAutoConfigurationTests {
 
 	}
 
+	@Configuration
 	public static class ContainerWithCommonsMultipartResolver {
 
 		@Bean

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/websocket/WebSocketAutoConfigurationTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -89,6 +89,7 @@ public class WebSocketAutoConfigurationTests {
 
 	}
 
+	@Configuration
 	static class CommonConfiguration {
 
 		@Bean

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/remote/client/RemoteClientConfiguration.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -133,6 +133,7 @@ public class RemoteClientConfiguration {
 	/**
 	 * LiveReload configuration.
 	 */
+	@Configuration
 	@ConditionalOnProperty(prefix = "spring.devtools.livereload", name = "enabled", matchIfMissing = true)
 	static class LiveReloadConfiguration {
 
@@ -179,6 +180,7 @@ public class RemoteClientConfiguration {
 	/**
 	 * Client configuration for remote update and restarts.
 	 */
+	@Configuration
 	@ConditionalOnProperty(prefix = "spring.devtools.remote.restart", name = "enabled", matchIfMissing = true)
 	static class RemoteRestartClientConfiguration {
 
@@ -242,6 +244,7 @@ public class RemoteClientConfiguration {
 	/**
 	 * Client configuration for remote debug HTTP tunneling.
 	 */
+	@Configuration
 	@ConditionalOnProperty(prefix = "spring.devtools.remote.debug", name = "enabled", matchIfMissing = true)
 	@ConditionalOnClass(Filter.class)
 	@Conditional(LocalDebugPortAvailableCondition.class)

spring-boot-samples/spring-boot-sample-parent-context/src/main/java/sample/parent/SampleParentContextApplication.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.dsl.IntegrationFlow;
 import org.springframework.integration.dsl.IntegrationFlows;
@@ -41,6 +42,7 @@ public class SampleParentContextApplication {
 				.child(SampleParentContextApplication.class).run(args);
 	}
 
+	@Configuration
 	@EnableAutoConfiguration
 	protected static class Parent {
 

spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/json/JsonTestersAutoConfiguration.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -70,8 +70,9 @@ public class JsonTestersAutoConfiguration {
 				null);
 	}
 
+	@Configuration
 	@ConditionalOnClass(ObjectMapper.class)
-	private static class JacksonJsonTestersConfiguration {
+	static class JacksonJsonTestersConfiguration {
 
 		@Bean
 		@Scope("prototype")
@@ -84,8 +85,9 @@ public class JsonTestersAutoConfiguration {
 
 	}
 
+	@Configuration
 	@ConditionalOnClass(Gson.class)
-	private static class GsonJsonTestersConfiguration {
+	static class GsonJsonTestersConfiguration {
 
 		@Bean
 		@Scope("prototype")

spring-boot/src/test/java/org/springframework/boot/diagnostics/analyzer/BeanCurrentlyInCreationFailureAnalyzerTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -242,6 +242,7 @@ public class BeanCurrentlyInCreationFailureAnalyzerTests {
 			return new BeanOne();
 		}
 
+		@org.springframework.context.annotation.Configuration
 		public static class BeanTwoConfiguration {
 
 			@SuppressWarnings("unused")
@@ -255,6 +256,7 @@ public class BeanCurrentlyInCreationFailureAnalyzerTests {
 
 		}
 
+		@org.springframework.context.annotation.Configuration
 		public static class BeanThreeConfiguration {
 
 			@Bean

spring-boot/src/test/java/org/springframework/boot/diagnostics/analyzer/NoUniqueBeanDefinitionFailureAnalyzerTests.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -154,6 +154,7 @@ public class NoUniqueBeanDefinitionFailureAnalyzerTests {
 
 	}
 
+	@Configuration
 	static class ParentProducer {
 
 		@Bean

spring-boot/src/test/java/org/springframework/boot/web/servlet/ServletContextInitializerBeansTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,6 +32,7 @@ import org.junit.Test;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -66,6 +67,7 @@ public class ServletContextInitializerBeansTests {
 		this.context = new AnnotationConfigApplicationContext(configuration);
 	}
 
+	@Configuration
 	static class ServletConfiguration {
 
 		@Bean
@@ -75,6 +77,7 @@ public class ServletContextInitializerBeansTests {
 
 	}
 
+	@Configuration
 	static class FilterConfiguration {
 
 		@Bean