Move Threading enum from spring-boot-autoconfigure to spring-boot

The enum itself is not specifically tied to auto-configuration so
spring-boot is a better place for it. The related condition,
`@ConditionalOnThreading`, remains in spring-boot-autoconfigure. This
aligns things with the similar `CloudPlatform` and
`@ConditionalOnCloudPlatform`.

Closes gh-46406

core/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/ConditionalOnThreading.java

@@ -22,7 +22,7 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.springframework.boot.autoconfigure.thread.Threading;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Conditional;
 
 /**

core/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnThreadingCondition.java

@@ -18,7 +18,7 @@ package org.springframework.boot.autoconfigure.condition;
 
 import java.util.Map;
 
-import org.springframework.boot.autoconfigure.thread.Threading;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Condition;
 import org.springframework.context.annotation.ConditionContext;
 import org.springframework.core.env.Environment;

core/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/task/TaskExecutorConfigurations.java

@@ -26,11 +26,11 @@ import org.springframework.boot.autoconfigure.condition.AnyNestedCondition;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.task.SimpleAsyncTaskExecutorBuilder;
 import org.springframework.boot.task.SimpleAsyncTaskExecutorCustomizer;
 import org.springframework.boot.task.ThreadPoolTaskExecutorBuilder;
 import org.springframework.boot.task.ThreadPoolTaskExecutorCustomizer;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;

core/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/task/TaskSchedulingConfigurations.java

@@ -23,11 +23,11 @@ import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.task.SimpleAsyncTaskSchedulerBuilder;
 import org.springframework.boot.task.SimpleAsyncTaskSchedulerCustomizer;
 import org.springframework.boot.task.ThreadPoolTaskSchedulerBuilder;
 import org.springframework.boot.task.ThreadPoolTaskSchedulerCustomizer;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.task.TaskDecorator;

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

@@ -20,8 +20,8 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.EnabledForJreRange;
 import org.junit.jupiter.api.condition.JRE;
 
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 

core/spring-boot/src/main/java/org/springframework/boot/thread/Threading.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.thread;
+package org.springframework.boot.thread;
 
 import org.springframework.boot.system.JavaVersion;
 import org.springframework.core.env.Environment;

core/spring-boot/src/main/java/org/springframework/boot/thread/package-info.java

@@ -17,4 +17,4 @@
 /**
  * Classes related to threads.
  */
-package org.springframework.boot.autoconfigure.thread;
+package org.springframework.boot.thread;

module/spring-boot-amqp/src/main/java/org/springframework/boot/amqp/autoconfigure/RabbitAnnotationDrivenConfiguration.java

@@ -31,7 +31,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.task.VirtualThreadTaskExecutor;

module/spring-boot-data-redis/src/main/java/org/springframework/boot/data/redis/autoconfigure/JedisConnectionConfiguration.java

@@ -27,10 +27,10 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.context.properties.PropertyMapper;
 import org.springframework.boot.ssl.SslBundle;
 import org.springframework.boot.ssl.SslOptions;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.task.SimpleAsyncTaskExecutor;

module/spring-boot-data-redis/src/main/java/org/springframework/boot/data/redis/autoconfigure/LettuceConnectionConfiguration.java

@@ -36,11 +36,11 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.data.redis.autoconfigure.RedisProperties.Lettuce.Cluster.Refresh;
 import org.springframework.boot.data.redis.autoconfigure.RedisProperties.Pool;
 import org.springframework.boot.ssl.SslBundle;
 import org.springframework.boot.ssl.SslOptions;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.task.SimpleAsyncTaskExecutor;

module/spring-boot-integration/src/main/java/org/springframework/boot/integration/autoconfigure/IntegrationAutoConfiguration.java

@@ -37,7 +37,6 @@ import org.springframework.boot.autoconfigure.condition.SearchStrategy;
 import org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration;
 import org.springframework.boot.autoconfigure.jmx.JmxProperties;
 import org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.context.properties.PropertyMapper;
 import org.springframework.boot.context.properties.source.MutuallyExclusiveConfigurationPropertiesException;
@@ -45,6 +44,7 @@ import org.springframework.boot.jdbc.init.DataSourceScriptDatabaseInitializer;
 import org.springframework.boot.sql.autoconfigure.init.OnDatabaseInitializationCondition;
 import org.springframework.boot.task.SimpleAsyncTaskSchedulerBuilder;
 import org.springframework.boot.task.ThreadPoolTaskSchedulerBuilder;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;

module/spring-boot-jetty/src/main/java/org/springframework/boot/jetty/autoconfigure/JettyWebServerConfiguration.java

@@ -18,9 +18,9 @@ package org.springframework.boot.jetty.autoconfigure;
 
 import org.springframework.boot.autoconfigure.condition.ConditionalOnNotWarDeployment;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.jetty.autoconfigure.reactive.JettyReactiveWebServerAutoConfiguration;
 import org.springframework.boot.jetty.autoconfigure.servlet.JettyServletWebServerAutoConfiguration;
+import org.springframework.boot.thread.Threading;
 import org.springframework.boot.web.server.autoconfigure.ServerProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;

module/spring-boot-kafka/src/main/java/org/springframework/boot/kafka/autoconfigure/KafkaAnnotationDrivenConfiguration.java

@@ -22,7 +22,7 @@ import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.task.SimpleAsyncTaskExecutor;

module/spring-boot-metrics/src/main/java/org/springframework/boot/metrics/autoconfigure/export/otlp/OtlpMetricsExportAutoConfiguration.java

@@ -28,13 +28,13 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.metrics.autoconfigure.CompositeMeterRegistryAutoConfiguration;
 import org.springframework.boot.metrics.autoconfigure.MetricsAutoConfiguration;
 import org.springframework.boot.metrics.autoconfigure.export.ConditionalOnEnabledMetricsExport;
 import org.springframework.boot.metrics.autoconfigure.export.simple.SimpleMetricsExportAutoConfiguration;
 import org.springframework.boot.opentelemetry.autoconfigure.OpenTelemetryProperties;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Bean;
 import org.springframework.core.env.Environment;
 import org.springframework.core.task.VirtualThreadTaskExecutor;

module/spring-boot-pulsar/src/main/java/org/springframework/boot/pulsar/autoconfigure/PulsarAutoConfiguration.java

@@ -31,7 +31,7 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBooleanProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
-import org.springframework.boot.autoconfigure.thread.Threading;
+import org.springframework.boot.thread.Threading;
 import org.springframework.boot.util.LambdaSafe;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/NotReactiveWebApplicationOrVirtualThreadsExecutorEnabledCondition.java

@@ -21,7 +21,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
 import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
 import org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration;
-import org.springframework.boot.autoconfigure.thread.Threading;
+import org.springframework.boot.thread.Threading;
 import org.springframework.context.annotation.Conditional;
 
 /**

module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerConfiguration.java

@@ -21,7 +21,7 @@ import org.apache.tomcat.websocket.server.WsSci;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnNotWarDeployment;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
-import org.springframework.boot.autoconfigure.thread.Threading;
+import org.springframework.boot.thread.Threading;
 import org.springframework.boot.tomcat.autoconfigure.reactive.TomcatReactiveWebServerAutoConfiguration;
 import org.springframework.boot.tomcat.autoconfigure.servlet.TomcatServletWebServerAutoConfiguration;
 import org.springframework.boot.web.server.autoconfigure.ServerProperties;

module/spring-boot-undertow/src/main/java/org/springframework/boot/undertow/autoconfigure/servlet/UndertowServletWebServerAutoConfiguration.java

@@ -31,8 +31,8 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnThreading;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
 import org.springframework.boot.autoconfigure.condition.SearchStrategy;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.thread.Threading;
 import org.springframework.boot.undertow.UndertowBuilderCustomizer;
 import org.springframework.boot.undertow.autoconfigure.UndertowServerProperties;
 import org.springframework.boot.undertow.autoconfigure.UndertowWebServerConfiguration;

module/spring-boot-webflux/src/main/java/org/springframework/boot/webflux/autoconfigure/WebFluxAutoConfiguration.java

@@ -35,7 +35,6 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplicat
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
 import org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration;
 import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProviders;
-import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.autoconfigure.web.ConditionalOnEnabledResourceChain;
 import org.springframework.boot.autoconfigure.web.WebProperties;
 import org.springframework.boot.autoconfigure.web.WebProperties.Resources;
@@ -46,6 +45,7 @@ import org.springframework.boot.context.properties.EnableConfigurationProperties
 import org.springframework.boot.convert.ApplicationConversionService;
 import org.springframework.boot.http.codec.CodecCustomizer;
 import org.springframework.boot.http.codec.autoconfigure.CodecsAutoConfiguration;
+import org.springframework.boot.thread.Threading;
 import org.springframework.boot.validation.autoconfigure.ValidatorAdapter;
 import org.springframework.boot.web.server.autoconfigure.ServerProperties;
 import org.springframework.boot.webflux.autoconfigure.WebFluxProperties.Format;