Merge branch '3.1.x' into 3.2.x

Closes gh-39091

buildSrc/build.gradle

@@ -31,8 +31,13 @@ if (versions.springFramework.contains("-")) {
 	}
 }
 
+checkstyle {
+	toolVersion = "10.12.4"
+}
+
 dependencies {
-	checkstyle "io.spring.javaformat:spring-javaformat-checkstyle:${javaFormatVersion}"
+	checkstyle("com.puppycrawl.tools:checkstyle:${checkstyle.toolVersion}")
+	checkstyle("io.spring.javaformat:spring-javaformat-checkstyle:${javaFormatVersion}")
 
 	implementation(platform("org.springframework:spring-framework-bom:${versions.springFramework}"))
 	implementation("com.diffplug.gradle:goomph:3.37.2")
@@ -58,10 +63,6 @@ dependencies {
 	testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 }
 
-checkstyle {
-	toolVersion = "10.12.4"
-}
-
 gradlePlugin {
 	plugins {
 		annotationProcessorPlugin {

buildSrc/src/main/java/org/springframework/boot/build/JavaConventions.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -243,6 +243,8 @@ class JavaConventions {
 		checkstyle.getConfigDirectory().set(project.getRootProject().file("src/checkstyle"));
 		String version = SpringJavaFormatPlugin.class.getPackage().getImplementationVersion();
 		DependencySet checkstyleDependencies = project.getConfigurations().getByName("checkstyle").getDependencies();
+		checkstyleDependencies
+			.add(project.getDependencies().create("com.puppycrawl.tools:checkstyle:" + checkstyle.getToolVersion()));
 		checkstyleDependencies
 			.add(project.getDependencies().create("io.spring.javaformat:spring-javaformat-checkstyle:" + version));
 	}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/cloudfoundry/servlet/SkipSslVerificationHttpRequestFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -62,7 +62,7 @@ class SkipSslVerificationHttpRequestFactory extends SimpleClientHttpRequestFacto
 		return context.getSocketFactory();
 	}
 
-	private static class SkipHostnameVerifier implements HostnameVerifier {
+	private static final class SkipHostnameVerifier implements HostnameVerifier {
 
 		@Override
 		public boolean verify(String s, SSLSession sslSession) {
@@ -71,7 +71,7 @@ class SkipSslVerificationHttpRequestFactory extends SimpleClientHttpRequestFacto
 
 	}
 
-	private static class SkipX509TrustManager implements X509TrustManager {
+	private static final class SkipX509TrustManager implements X509TrustManager {
 
 		@Override
 		public X509Certificate[] getAcceptedIssuers() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/logging/LogFileWebEndpointAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -54,7 +54,7 @@ public class LogFileWebEndpointAutoConfiguration {
 		return new LogFileWebEndpoint(logFile.getIfAvailable(), properties.getExternalFile());
 	}
 
-	private static class LogFileCondition extends SpringBootCondition {
+	private static final class LogFileCondition extends SpringBootCondition {
 
 		@Override
 		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/jersey/JerseyServerMetricsAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -92,7 +92,7 @@ public class JerseyServerMetricsAutoConfiguration {
 	/**
 	 * An {@link AnnotationFinder} that uses {@link AnnotationUtils}.
 	 */
-	private static class AnnotationUtilsAnnotationFinder implements AnnotationFinder {
+	private static final class AnnotationUtilsAnnotationFinder implements AnnotationFinder {
 
 		@Override
 		public <A extends Annotation> A findAnnotation(AnnotatedElement annotatedElement, Class<A> annotationType) {

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/security/servlet/EndpointRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -311,7 +311,7 @@ public final class EndpointRequest {
 	/**
 	 * Factory used to create a {@link RequestMatcher}.
 	 */
-	private static class RequestMatcherFactory {
+	private static final class RequestMatcherFactory {
 
 		RequestMatcher antPath(RequestMatcherProvider matcherProvider, String... parts) {
 			StringBuilder pattern = new StringBuilder();

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/cloudfoundry/reactive/CloudFoundryReactiveHealthEndpointWebExtensionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -75,7 +75,7 @@ class CloudFoundryReactiveHealthEndpointWebExtensionTests {
 		});
 	}
 
-	private static class TestHealthIndicator implements HealthIndicator {
+	private static final class TestHealthIndicator implements HealthIndicator {
 
 		@Override
 		public Health health() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/cloudfoundry/servlet/CloudFoundryHealthEndpointWebExtensionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -70,7 +70,7 @@ class CloudFoundryHealthEndpointWebExtensionTests {
 		});
 	}
 
-	private static class TestHealthIndicator implements HealthIndicator {
+	private static final class TestHealthIndicator implements HealthIndicator {
 
 		@Override
 		public Health health() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/endpoint/web/documentation/HealthEndpointDocumentationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -138,7 +138,7 @@ class HealthEndpointDocumentationTests extends MockMvcEndpointDocumentationTests
 
 	}
 
-	private static class TestHealthEndpointGroup implements HealthEndpointGroup {
+	private static final class TestHealthEndpointGroup implements HealthEndpointGroup {
 
 		private final StatusAggregator statusAggregator = new SimpleStatusAggregator();
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/observation/ObservationAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -561,11 +561,11 @@ class ObservationAutoConfigurationTests {
 
 	}
 
-	private static class CustomContext extends Context {
+	private static final class CustomContext extends Context {
 
 	}
 
-	private static class CalledHandlers {
+	private static final class CalledHandlers {
 
 		private final List<ObservationHandler<?>> calledHandlers = new ArrayList<>();
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/observation/ObservationRegistryConfigurerIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -74,7 +74,7 @@ class ObservationRegistryConfigurerIntegrationTests {
 
 	}
 
-	private static class CalledCustomizers {
+	private static final class CalledCustomizers {
 
 		private final List<ObservationRegistryCustomizer<?>> customizers = new ArrayList<>();
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/opentelemetry/OpenTelemetryAutoConfigurationTests.java

@@ -140,7 +140,7 @@ class OpenTelemetryAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class UserConfiguration {
+	private static final class UserConfiguration {
 
 		@Bean
 		OpenTelemetry customOpenTelemetry() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/opentelemetry/OpenTelemetryPropertiesTests.java

@@ -48,7 +48,7 @@ class OpenTelemetryPropertiesTests {
 
 	@Configuration(proxyBeanMethods = false)
 	@EnableConfigurationProperties(OpenTelemetryProperties.class)
-	private static class TestConfiguration {
+	private static final class TestConfiguration {
 
 	}
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/r2dbc/R2dbcObservationAutoConfigurationTests.java

@@ -108,7 +108,7 @@ class R2dbcObservationAutoConfigurationTests {
 		return handler;
 	}
 
-	private static class CapturingObservationHandler implements ObservationHandler<Context> {
+	private static final class CapturingObservationHandler implements ObservationHandler<Context> {
 
 		private final AtomicReference<Context> context = new AtomicReference<>();
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/BraveAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -443,7 +443,7 @@ class BraveAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		Tracing customTracing() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/MicrometerTracingAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -162,7 +162,7 @@ class MicrometerTracingAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class TracerConfiguration {
+	private static final class TracerConfiguration {
 
 		@Bean
 		Tracer tracer() {
@@ -172,7 +172,7 @@ class MicrometerTracingAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class PropagatorConfiguration {
+	private static final class PropagatorConfiguration {
 
 		@Bean
 		Propagator propagator() {
@@ -182,7 +182,7 @@ class MicrometerTracingAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		DefaultTracingObservationHandler customDefaultTracingObservationHandler() {
@@ -218,7 +218,7 @@ class MicrometerTracingAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class SpanTagAnnotationHandlerConfiguration {
+	private static final class SpanTagAnnotationHandlerConfiguration {
 
 		@Bean
 		SpanTagAnnotationHandler spanTagAnnotationHandler() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/NoopTracerAutoConfigurationTests.java

@@ -65,7 +65,7 @@ class NoopTracerAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomTracerConfiguration {
+	private static final class CustomTracerConfiguration {
 
 		@Bean
 		Tracer customTracer() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/OpenTelemetryAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -309,7 +309,7 @@ class OpenTelemetryAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class MeterProviderConfiguration {
+	private static final class MeterProviderConfiguration {
 
 		@Bean
 		MeterProvider meterProvider() {
@@ -322,7 +322,7 @@ class OpenTelemetryAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class AdditionalSpanProcessorConfiguration {
+	private static final class AdditionalSpanProcessorConfiguration {
 
 		@Bean
 		SpanProcessor customSpanProcessor() {
@@ -332,7 +332,7 @@ class OpenTelemetryAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class MultipleSpanExporterConfiguration {
+	private static final class MultipleSpanExporterConfiguration {
 
 		@Bean
 		SpanExporter spanExporter1() {
@@ -347,7 +347,7 @@ class OpenTelemetryAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		SpanProcessors customSpanProcessors() {
@@ -427,7 +427,7 @@ class OpenTelemetryAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class SdkTracerProviderCustomizationConfiguration {
+	private static final class SdkTracerProviderCustomizationConfiguration {
 
 		@Bean
 		@Order(1)
@@ -449,7 +449,7 @@ class OpenTelemetryAutoConfigurationTests {
 
 	}
 
-	private static class DummySpanExporter implements SpanExporter {
+	private static final class DummySpanExporter implements SpanExporter {
 
 		@Override
 		public CompletableResultCode export(Collection<SpanData> spans) {
@@ -469,7 +469,7 @@ class OpenTelemetryAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class InMemoryRecordingSpanExporterConfiguration {
+	private static final class InMemoryRecordingSpanExporterConfiguration {
 
 		@Bean
 		InMemoryRecordingSpanExporter spanExporter() {
@@ -478,7 +478,7 @@ class OpenTelemetryAutoConfigurationTests {
 
 	}
 
-	private static class InMemoryRecordingSpanExporter implements SpanExporter {
+	private static final class InMemoryRecordingSpanExporter implements SpanExporter {
 
 		private final List<SpanData> exportedSpans = new ArrayList<>();
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/otlp/OtlpAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -127,7 +127,7 @@ class OtlpAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomHttpExporterConfiguration {
+	private static final class CustomHttpExporterConfiguration {
 
 		@Bean
 		OtlpHttpSpanExporter customOtlpHttpSpanExporter() {
@@ -137,7 +137,7 @@ class OtlpAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomGrpcExporterConfiguration {
+	private static final class CustomGrpcExporterConfiguration {
 
 		@Bean
 		OtlpGrpcSpanExporter customOtlpGrpcSpanExporter() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/prometheus/PrometheusExemplarsAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -116,7 +116,7 @@ class PrometheusExemplarsAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		static final SpanContextSupplier SUPPLIER = mock(SpanContextSupplier.class);
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/wavefront/WavefrontTracingAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -173,7 +173,7 @@ class WavefrontTracingAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		ApplicationTags customApplicationTags() {
@@ -203,7 +203,7 @@ class WavefrontTracingAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class WavefrontSenderConfiguration {
+	private static final class WavefrontSenderConfiguration {
 
 		@Bean
 		WavefrontSender wavefrontSender() {
@@ -213,7 +213,7 @@ class WavefrontTracingAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class MeterRegistryConfiguration {
+	private static final class MeterRegistryConfiguration {
 
 		@Bean
 		MeterRegistry meterRegistry() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -87,7 +87,7 @@ class ZipkinAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		BytesEncoder<Span> customBytesEncoder() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurationsBraveConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -89,7 +89,7 @@ class ZipkinConfigurationsBraveConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class ReporterConfiguration {
+	private static final class ReporterConfiguration {
 
 		@Bean
 		@SuppressWarnings("unchecked")
@@ -100,7 +100,7 @@ class ZipkinConfigurationsBraveConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		@SuppressWarnings("unchecked")
@@ -111,7 +111,7 @@ class ZipkinConfigurationsBraveConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomSpanHandlerConfiguration {
+	private static final class CustomSpanHandlerConfiguration {
 
 		@Bean
 		SpanHandler customSpanHandler() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurationsOpenTelemetryConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -80,7 +80,7 @@ class ZipkinConfigurationsOpenTelemetryConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class SenderConfiguration {
+	private static final class SenderConfiguration {
 
 		@Bean
 		Sender sender() {
@@ -90,7 +90,7 @@ class ZipkinConfigurationsOpenTelemetryConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		ZipkinSpanExporter customZipkinSpanExporter() {
@@ -100,7 +100,7 @@ class ZipkinConfigurationsOpenTelemetryConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class BaseConfiguration {
+	private static final class BaseConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurationsReporterConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -64,7 +64,7 @@ class ZipkinConfigurationsReporterConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class SenderConfiguration {
+	private static final class SenderConfiguration {
 
 		@Bean
 		Sender sender() {
@@ -74,7 +74,7 @@ class ZipkinConfigurationsReporterConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		@SuppressWarnings("unchecked")
@@ -85,7 +85,7 @@ class ZipkinConfigurationsReporterConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class BaseConfiguration {
+	private static final class BaseConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurationsSenderConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -173,7 +173,7 @@ class ZipkinConfigurationsSenderConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class RestTemplateConfiguration {
+	private static final class RestTemplateConfiguration {
 
 		@Bean
 		ZipkinRestTemplateBuilderCustomizer zipkinRestTemplateBuilderCustomizer() {
@@ -183,7 +183,7 @@ class ZipkinConfigurationsSenderConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class WebClientConfiguration {
+	private static final class WebClientConfiguration {
 
 		@Bean
 		ZipkinWebClientBuilderCustomizer webClientBuilder() {
@@ -193,7 +193,7 @@ class ZipkinConfigurationsSenderConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomConfiguration {
+	private static final class CustomConfiguration {
 
 		@Bean
 		Sender customSender() {
@@ -202,7 +202,7 @@ class ZipkinConfigurationsSenderConfigurationTests {
 
 	}
 
-	private static class DummyZipkinRestTemplateBuilderCustomizer implements ZipkinRestTemplateBuilderCustomizer {
+	private static final class DummyZipkinRestTemplateBuilderCustomizer implements ZipkinRestTemplateBuilderCustomizer {
 
 		@Override
 		public RestTemplateBuilder customize(RestTemplateBuilder restTemplateBuilder) {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinWebClientSenderTests.java

@@ -187,7 +187,7 @@ class ZipkinWebClientSenderTests extends ZipkinHttpSenderTests {
 		dispatcher.clear();
 	}
 
-	private static class ClearableDispatcher extends QueueDispatcher {
+	private static final class ClearableDispatcher extends QueueDispatcher {
 
 		void clear() {
 			getResponseQueue().clear();

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/context/properties/ConfigurationPropertiesReportEndpoint.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -402,7 +402,7 @@ public class ConfigurationPropertiesReportEndpoint implements ApplicationContext
 	 * Extension to {@link JacksonAnnotationIntrospector} to suppress CGLIB generated bean
 	 * properties.
 	 */
-	private static class ConfigurationPropertiesAnnotationIntrospector extends JacksonAnnotationIntrospector {
+	private static final class ConfigurationPropertiesAnnotationIntrospector extends JacksonAnnotationIntrospector {
 
 		@Override
 		public Object findFilterId(Annotated a) {
@@ -425,7 +425,7 @@ public class ConfigurationPropertiesReportEndpoint implements ApplicationContext
 	 * <li>Properties that throw an exception when retrieving their value.
 	 * </ul>
 	 */
-	private static class ConfigurationPropertiesPropertyFilter extends SimpleBeanPropertyFilter {
+	private static final class ConfigurationPropertiesPropertyFilter extends SimpleBeanPropertyFilter {
 
 		private static final Log logger = LogFactory.getLog(ConfigurationPropertiesPropertyFilter.class);
 

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/invoke/reflect/OperationMethodParameter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -81,7 +81,7 @@ class OperationMethodParameter implements OperationParameter {
 		return this.name + " of type " + this.parameter.getType().getName();
 	}
 
-	private static class Jsr305 {
+	private static final class Jsr305 {
 
 		boolean isMandatory(Parameter parameter) {
 			MergedAnnotation<Nonnull> annotation = MergedAnnotations.from(parameter).get(Nonnull.class);

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/jmx/EndpointMBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -172,7 +172,7 @@ public class EndpointMBean implements DynamicMBean {
 		return new AttributeList();
 	}
 
-	private static class ReactiveHandler {
+	private static final class ReactiveHandler {
 
 		static Object handle(Object result) {
 			if (result instanceof Flux) {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/jmx/annotation/DiscoveredJmxOperation.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -182,7 +182,7 @@ class DiscoveredJmxOperation extends AbstractDiscoveredOperation implements JmxO
 	/**
 	 * Utility to convert to JMX supported types.
 	 */
-	private static class JmxType {
+	private static final class JmxType {
 
 		static Class<?> get(Class<?> source) {
 			if (source.isEnum()) {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/servlet/AbstractWebMvcEndpointHandlerMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -397,7 +397,7 @@ public abstract class AbstractWebMvcEndpointHandlerMapping extends RequestMappin
 			return body;
 		}
 
-		private static class FluxBodyConverter implements Function<Object, Object> {
+		private static final class FluxBodyConverter implements Function<Object, Object> {
 
 			@Override
 			public Object apply(Object body) {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleStatusAggregator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -100,7 +100,7 @@ public class SimpleStatusAggregator implements StatusAggregator {
 	/**
 	 * {@link Comparator} used to order {@link Status}.
 	 */
-	private class StatusComparator implements Comparator<Status> {
+	private final class StatusComparator implements Comparator<Status> {
 
 		@Override
 		public int compare(Status s1, Status s2) {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/jdbc/DataSourceHealthIndicator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -163,7 +163,7 @@ public class DataSourceHealthIndicator extends AbstractHealthIndicator implement
 	/**
 	 * {@link RowMapper} that expects and returns results from a single column.
 	 */
-	private static class SingleColumnRowMapper implements RowMapper<Object> {
+	private static final class SingleColumnRowMapper implements RowMapper<Object> {
 
 		@Override
 		public Object mapRow(ResultSet rs, int rowNum) throws SQLException {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/ldap/LdapHealthIndicator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -51,7 +51,7 @@ public class LdapHealthIndicator extends AbstractHealthIndicator {
 		builder.up().withDetail("version", version);
 	}
 
-	private static class VersionContextExecutor implements ContextExecutor<String> {
+	private static final class VersionContextExecutor implements ContextExecutor<String> {
 
 		@Override
 		public String executeWithContext(DirContext ctx) throws NamingException {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/cache/CacheMetricsRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -96,7 +96,7 @@ public class CacheMetricsRegistrar {
 		return cache;
 	}
 
-	private static class TransactionAwareCacheDecoratorHandler {
+	private static final class TransactionAwareCacheDecoratorHandler {
 
 		private static Cache unwrapIfNecessary(Cache cache) {
 			try {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/neo4j/Neo4jReactiveHealthIndicator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -88,7 +88,7 @@ public final class Neo4jReactiveHealthIndicator extends AbstractReactiveHealthIn
 	 * Builder used to create a {@link Neo4jHealthDetails} from a {@link Record} and a
 	 * {@link ResultSummary}.
 	 */
-	private static class Neo4jHealthDetailsBuilder {
+	private static final class Neo4jHealthDetailsBuilder {
 
 		private Record record;
 

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/security/AuthenticationAuditListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -93,7 +93,7 @@ public class AuthenticationAuditListener extends AbstractAuthenticationAuditList
 		publish(new AuditEvent(event.getAuthentication().getName(), AUTHENTICATION_SUCCESS, data));
 	}
 
-	private static class WebAuditListener {
+	private static final class WebAuditListener {
 
 		void process(AuthenticationAuditListener listener, AbstractAuthenticationEvent input) {
 			if (listener != null) {

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/annotation/OperationReflectiveProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -95,7 +95,7 @@ class OperationReflectiveProcessorTests {
 	}
 
 	@SuppressWarnings("unused")
-	private static class Methods {
+	private static final class Methods {
 
 		private String string() {
 			return null;

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/invoker/cache/CachingOperationInvokerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -261,7 +261,7 @@ class CachingOperationInvokerTests {
 		then(target).should(times(1)).invoke(contextManagement);
 	}
 
-	private static class MonoOperationInvoker implements OperationInvoker {
+	private static final class MonoOperationInvoker implements OperationInvoker {
 
 		static AtomicInteger invocations = new AtomicInteger();
 
@@ -275,7 +275,7 @@ class CachingOperationInvokerTests {
 
 	}
 
-	private static class FluxOperationInvoker implements OperationInvoker {
+	private static final class FluxOperationInvoker implements OperationInvoker {
 
 		static AtomicInteger invocations = new AtomicInteger();
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationImportSelector.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -390,7 +390,7 @@ public class AutoConfigurationImportSelector implements DeferredImportSelector,
 
 	}
 
-	private static class AutoConfigurationGroup
+	private static final class AutoConfigurationGroup
 			implements DeferredImportSelector.Group, BeanClassLoaderAware, BeanFactoryAware, ResourceLoaderAware {
 
 		private final Map<String, AnnotationMetadata> entries = new LinkedHashMap<>();

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -139,7 +139,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 	/**
 	 * Early initializer for Spring MessageConverters.
 	 */
-	private static class MessageConverterInitializer implements Runnable {
+	private static final class MessageConverterInitializer implements Runnable {
 
 		@Override
 		public void run() {
@@ -151,7 +151,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 	/**
 	 * Early initializer for jakarta.validation.
 	 */
-	private static class ValidationInitializer implements Runnable {
+	private static final class ValidationInitializer implements Runnable {
 
 		@Override
 		public void run() {
@@ -164,7 +164,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 	/**
 	 * Early initializer for Jackson.
 	 */
-	private static class JacksonInitializer implements Runnable {
+	private static final class JacksonInitializer implements Runnable {
 
 		@Override
 		public void run() {
@@ -176,7 +176,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 	/**
 	 * Early initializer for Spring's ConversionService.
 	 */
-	private static class ConversionServiceInitializer implements Runnable {
+	private static final class ConversionServiceInitializer implements Runnable {
 
 		@Override
 		public void run() {
@@ -185,7 +185,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 
 	}
 
-	private static class CharsetInitializer implements Runnable {
+	private static final class CharsetInitializer implements Runnable {
 
 		@Override
 		public void run() {
@@ -194,7 +194,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 
 	}
 
-	private static class TomcatInitializer implements Runnable {
+	private static final class TomcatInitializer implements Runnable {
 
 		@Override
 		public void run() {
@@ -204,7 +204,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 
 	}
 
-	private static class JdkInitializer implements Runnable {
+	private static final class JdkInitializer implements Runnable {
 
 		@Override
 		public void run() {

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/cassandra/CassandraAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -277,7 +277,7 @@ public class CassandraAutoConfiguration {
 		return connectionDetails.getContactPoints().stream().map((node) -> node.host() + ":" + node.port()).toList();
 	}
 
-	private static class CassandraDriverOptions {
+	private static final class CassandraDriverOptions {
 
 		private final Map<String, String> options = new LinkedHashMap<>();
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/ConditionEvaluationReport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -291,7 +291,7 @@ public final class ConditionEvaluationReport {
 
 	}
 
-	private static class AncestorsMatchedCondition implements Condition {
+	private static final class AncestorsMatchedCondition implements Condition {
 
 		@Override
 		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/cassandra/CassandraReactiveRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class CassandraReactiveRepositoriesRegistrar extends AbstractRepositoryConfigura
 	}
 
 	@EnableReactiveCassandraRepositories
-	private static class EnableReactiveCassandraRepositoriesConfiguration {
+	private static final class EnableReactiveCassandraRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/cassandra/CassandraRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class CassandraRepositoriesRegistrar extends AbstractRepositoryConfigurationSour
 	}
 
 	@EnableCassandraRepositories
-	private static class EnableCassandraRepositoriesConfiguration {
+	private static final class EnableCassandraRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/couchbase/CouchbaseReactiveRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class CouchbaseReactiveRepositoriesRegistrar extends AbstractRepositoryConfigura
 	}
 
 	@EnableReactiveCouchbaseRepositories
-	private static class EnableReactiveCouchbaseRepositoriesConfiguration {
+	private static final class EnableReactiveCouchbaseRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/couchbase/CouchbaseRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class CouchbaseRepositoriesRegistrar extends AbstractRepositoryConfigurationSour
 	}
 
 	@EnableCouchbaseRepositories
-	private static class EnableCouchbaseRepositoriesConfiguration {
+	private static final class EnableCouchbaseRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/elasticsearch/ElasticsearchRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -49,7 +49,7 @@ class ElasticsearchRepositoriesRegistrar extends AbstractRepositoryConfiguration
 	}
 
 	@EnableElasticsearchRepositories
-	private static class EnableElasticsearchRepositoriesConfiguration {
+	private static final class EnableElasticsearchRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/elasticsearch/ReactiveElasticsearchRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class ReactiveElasticsearchRepositoriesRegistrar extends AbstractRepositoryConfi
 	}
 
 	@EnableReactiveElasticsearchRepositories
-	private static class EnableElasticsearchRepositoriesConfiguration {
+	private static final class EnableElasticsearchRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/jdbc/JdbcRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class JdbcRepositoriesRegistrar extends AbstractRepositoryConfigurationSourceSup
 	}
 
 	@EnableJdbcRepositories
-	private static class EnableJdbcRepositoriesConfiguration {
+	private static final class EnableJdbcRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/jpa/EnversRevisionRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -34,7 +34,7 @@ class EnversRevisionRepositoriesRegistrar extends JpaRepositoriesRegistrar {
 	}
 
 	@EnableJpaRepositories(repositoryFactoryBeanClass = EnversRevisionRepositoryFactoryBean.class)
-	private static class EnableJpaRepositoriesConfiguration {
+	private static final class EnableJpaRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/jpa/JpaRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -74,7 +74,7 @@ class JpaRepositoriesRegistrar extends AbstractRepositoryConfigurationSourceSupp
 	}
 
 	@EnableJpaRepositories
-	private static class EnableJpaRepositoriesConfiguration {
+	private static final class EnableJpaRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/ldap/LdapRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class LdapRepositoriesRegistrar extends AbstractRepositoryConfigurationSourceSup
 	}
 
 	@EnableLdapRepositories
-	private static class EnableLdapRepositoriesConfiguration {
+	private static final class EnableLdapRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/mongo/MongoReactiveRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class MongoReactiveRepositoriesRegistrar extends AbstractRepositoryConfiguration
 	}
 
 	@EnableReactiveMongoRepositories
-	private static class EnableReactiveMongoRepositoriesConfiguration {
+	private static final class EnableReactiveMongoRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/mongo/MongoRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class MongoRepositoriesRegistrar extends AbstractRepositoryConfigurationSourceSu
 	}
 
 	@EnableMongoRepositories
-	private static class EnableMongoRepositoriesConfiguration {
+	private static final class EnableMongoRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/neo4j/Neo4jReactiveRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class Neo4jReactiveRepositoriesRegistrar extends AbstractRepositoryConfiguration
 	}
 
 	@EnableReactiveNeo4jRepositories
-	private static class EnableReactiveNeo4jRepositoriesConfiguration {
+	private static final class EnableReactiveNeo4jRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/neo4j/Neo4jRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class Neo4jRepositoriesRegistrar extends AbstractRepositoryConfigurationSourceSu
 	}
 
 	@EnableNeo4jRepositories
-	private static class EnableNeo4jRepositoriesConfiguration {
+	private static final class EnableNeo4jRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/r2dbc/R2dbcRepositoriesAutoConfigureRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class R2dbcRepositoriesAutoConfigureRegistrar extends AbstractRepositoryConfigur
 	}
 
 	@EnableR2dbcRepositories
-	private static class EnableR2dbcRepositoriesConfiguration {
+	private static final class EnableR2dbcRepositoriesConfiguration {
 
 	}
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -212,7 +212,7 @@ class LettuceConnectionConfiguration extends RedisConnectionConfiguration {
 	/**
 	 * Inner class to allow optional commons-pool2 dependency.
 	 */
-	private static class PoolBuilderFactory {
+	private static final class PoolBuilderFactory {
 
 		LettuceClientConfigurationBuilder createBuilder(Pool properties) {
 			return LettucePoolingClientConfiguration.builder().poolConfig(getPoolConfig(properties));

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/redis/RedisRepositoriesRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -48,7 +48,7 @@ class RedisRepositoriesRegistrar extends AbstractRepositoryConfigurationSourceSu
 	}
 
 	@EnableRedisRepositories
-	private static class EnableRedisRepositoriesConfiguration {
+	private static final class EnableRedisRepositoriesConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/HttpMessageConvertersAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -94,7 +94,7 @@ public class HttpMessageConvertersAutoConfiguration {
 		}
 
 		@ConditionalOnWebApplication(type = Type.REACTIVE)
-		private static class ReactiveWebApplication {
+		private static final class ReactiveWebApplication {
 
 		}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/integration/IntegrationAutoConfigurationScanRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -59,7 +59,7 @@ class IntegrationAutoConfigurationScanRegistrar extends IntegrationComponentScan
 	}
 
 	@IntegrationComponentScan
-	private static class IntegrationComponentScanConfiguration {
+	private static final class IntegrationComponentScanConfiguration {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/kafka/KafkaProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -1757,7 +1757,7 @@ public class KafkaProperties {
 	}
 
 	@SuppressWarnings("serial")
-	private static class Properties extends HashMap<String, Object> {
+	private static final class Properties extends HashMap<String, Object> {
 
 		<V> java.util.function.Consumer<V> in(String key) {
 			return (value) -> put(key, value);

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/template/TemplateAvailabilityProviders.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -153,7 +153,7 @@ public class TemplateAvailabilityProviders {
 		return null;
 	}
 
-	private static class NoTemplateAvailabilityProvider implements TemplateAvailabilityProvider {
+	private static final class NoTemplateAvailabilityProvider implements TemplateAvailabilityProvider {
 
 		@Override
 		public boolean isTemplateAvailable(String view, Environment environment, ClassLoader classLoader,

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/client/NotReactiveWebApplicationCondition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -33,7 +33,7 @@ class NotReactiveWebApplicationCondition extends NoneNestedConditions {
 	}
 
 	@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.REACTIVE)
-	private static class ReactiveWebApplication {
+	private static final class ReactiveWebApplication {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/client/RestTemplateAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/error/AbstractErrorWebExceptionHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -330,7 +330,7 @@ public abstract class AbstractErrorWebExceptionHandler implements ErrorWebExcept
 		return response.writeTo(exchange, new ResponseContext());
 	}
 
-	private class ResponseContext implements ServerResponse.Context {
+	private final class ResponseContext implements ServerResponse.Context {
 
 		@Override
 		public List<HttpMessageWriter<?>> messageWriters() {

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/DispatcherServletAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -133,7 +133,7 @@ public class DispatcherServletAutoConfiguration {
 	}
 
 	@Order(Ordered.LOWEST_PRECEDENCE - 10)
-	private static class DefaultDispatcherServletCondition extends SpringBootCondition {
+	private static final class DefaultDispatcherServletCondition extends SpringBootCondition {
 
 		@Override
 		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
@@ -160,7 +160,7 @@ public class DispatcherServletAutoConfiguration {
 	}
 
 	@Order(Ordered.LOWEST_PRECEDENCE - 10)
-	private static class DispatcherServletRegistrationCondition extends SpringBootCondition {
+	private static final class DispatcherServletRegistrationCondition extends SpringBootCondition {
 
 		@Override
 		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/error/ErrorMvcAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -169,7 +169,7 @@ public class ErrorMvcAutoConfiguration {
 	/**
 	 * {@link SpringBootCondition} that matches when no error template view is detected.
 	 */
-	private static class ErrorTemplateMissingCondition extends SpringBootCondition {
+	private static final class ErrorTemplateMissingCondition extends SpringBootCondition {
 
 		@Override
 		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
@@ -188,7 +188,7 @@ public class ErrorMvcAutoConfiguration {
 	/**
 	 * Simple {@link View} implementation that writes a default HTML error page.
 	 */
-	private static class StaticView implements View {
+	private static final class StaticView implements View {
 
 		private static final MediaType TEXT_HTML_UTF8 = new MediaType("text", "html", StandardCharsets.UTF_8);
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/websocket/servlet/UndertowWebSocketServletWebServerCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -44,7 +44,7 @@ public class UndertowWebSocketServletWebServerCustomizer
 		return 0;
 	}
 
-	private static class WebsocketDeploymentInfoCustomizer implements UndertowDeploymentInfoCustomizer {
+	private static final class WebsocketDeploymentInfoCustomizer implements UndertowDeploymentInfoCustomizer {
 
 		@Override
 		public void customize(DeploymentInfo deploymentInfo) {

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/AutoConfigurationImportSelectorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -216,7 +216,7 @@ class AutoConfigurationImportSelectorTests {
 		return ImportCandidates.load(AutoConfiguration.class, getClass().getClassLoader()).getCandidates();
 	}
 
-	private class TestAutoConfigurationImportSelector extends AutoConfigurationImportSelector {
+	private final class TestAutoConfigurationImportSelector extends AutoConfigurationImportSelector {
 
 		private AutoConfigurationImportEvent lastEvent;
 
@@ -269,54 +269,54 @@ class AutoConfigurationImportSelectorTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private class TestConfiguration {
+	private final class TestConfiguration {
 
 	}
 
 	@EnableAutoConfiguration
-	private class BasicEnableAutoConfiguration {
+	private final class BasicEnableAutoConfiguration {
 
 	}
 
 	@EnableAutoConfiguration(exclude = FreeMarkerAutoConfiguration.class)
-	private class EnableAutoConfigurationWithClassExclusions {
+	private final class EnableAutoConfigurationWithClassExclusions {
 
 	}
 
 	@SpringBootApplication(exclude = FreeMarkerAutoConfiguration.class)
-	private class SpringBootApplicationWithClassExclusions {
+	private final class SpringBootApplicationWithClassExclusions {
 
 	}
 
 	@EnableAutoConfiguration(excludeName = "org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration")
-	private class EnableAutoConfigurationWithClassNameExclusions {
+	private final class EnableAutoConfigurationWithClassNameExclusions {
 
 	}
 
 	@EnableAutoConfiguration(exclude = MustacheAutoConfiguration.class,
 			excludeName = "org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration")
-	private class EnableAutoConfigurationWithClassAndClassNameExclusions {
+	private final class EnableAutoConfigurationWithClassAndClassNameExclusions {
 
 	}
 
 	@EnableAutoConfiguration(exclude = TestConfiguration.class)
-	private class EnableAutoConfigurationWithFaultyClassExclude {
+	private final class EnableAutoConfigurationWithFaultyClassExclude {
 
 	}
 
 	@EnableAutoConfiguration(
 			excludeName = "org.springframework.boot.autoconfigure.AutoConfigurationImportSelectorTests.TestConfiguration")
-	private class EnableAutoConfigurationWithFaultyClassNameExclude {
+	private final class EnableAutoConfigurationWithFaultyClassNameExclude {
 
 	}
 
 	@EnableAutoConfiguration(excludeName = "org.springframework.boot.autoconfigure.DoesNotExist1")
-	private class EnableAutoConfigurationWithAbsentClassNameExclude {
+	private final class EnableAutoConfigurationWithAbsentClassNameExclude {
 
 	}
 
 	@SpringBootApplication(excludeName = "org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration")
-	private class SpringBootApplicationWithClassNameExclusions {
+	private final class SpringBootApplicationWithClassNameExclusions {
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/r2dbc/R2dbcAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -405,7 +405,7 @@ class R2dbcAutoConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static class CustomizerConfiguration {
+	private static final class CustomizerConfiguration {
 
 		@Bean
 		ConnectionFactoryOptionsBuilderCustomizer customizer() {

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/ssl/FileWatcherTests.java

@@ -165,7 +165,7 @@ class FileWatcherTests {
 		}
 	}
 
-	private static class WaitingCallback implements Runnable {
+	private static final class WaitingCallback implements Runnable {
 
 		private final CountDownLatch latch = new CountDownLatch(1);
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/task/ScheduledBeanLazyInitializationExcludeFilterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -52,7 +52,7 @@ class ScheduledBeanLazyInitializationExcludeFilterTests {
 		return this.filter.isExcluded("test", new RootBeanDefinition(type), type);
 	}
 
-	private static class TestBean {
+	private static final class TestBean {
 
 		@Scheduled
 		void doStuff() {
@@ -60,7 +60,7 @@ class ScheduledBeanLazyInitializationExcludeFilterTests {
 
 	}
 
-	private static class AnotherTestBean {
+	private static final class AnotherTestBean {
 
 		@Schedules({ @Scheduled(fixedRate = 5000), @Scheduled(fixedRate = 2500) })
 		void doStuff() {

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/livereload/LiveReloadServer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -298,7 +298,7 @@ public class LiveReloadServer {
 	/**
 	 * {@link ThreadFactory} to create the worker threads.
 	 */
-	private static class WorkerThreadFactory implements ThreadFactory {
+	private static final class WorkerThreadFactory implements ThreadFactory {
 
 		private final AtomicInteger threadNumber = new AtomicInteger(1);
 

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/ClassLoaderFilesResourcePatternResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -212,7 +212,7 @@ final class ClassLoaderFilesResourcePatternResolver implements ResourcePatternRe
 	 * {@link ResourcePatternResolverFactory} to be used when the classloader can access
 	 * {@link WebApplicationContext}.
 	 */
-	private static class WebResourcePatternResolverFactory extends ResourcePatternResolverFactory {
+	private static final class WebResourcePatternResolverFactory extends ResourcePatternResolverFactory {
 
 		@Override
 		public ResourcePatternResolver getResourcePatternResolver(AbstractApplicationContext applicationContext,

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/RestartScopeInitializer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -37,7 +37,7 @@ public class RestartScopeInitializer implements ApplicationContextInitializer<Co
 	/**
 	 * {@link Scope} that stores beans as {@link Restarter} attributes.
 	 */
-	private static class RestartScope implements Scope {
+	private static final class RestartScope implements Scope {
 
 		@Override
 		public Object get(String name, ObjectFactory<?> objectFactory) {

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/Restarter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -617,7 +617,7 @@ public class Restarter {
 	/**
 	 * {@link ThreadFactory} that creates a leak safe thread.
 	 */
-	private class LeakSafeThreadFactory implements ThreadFactory {
+	private final class LeakSafeThreadFactory implements ThreadFactory {
 
 		@Override
 		public Thread newThread(Runnable runnable) {

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/SilentExitExceptionHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -92,7 +92,7 @@ class SilentExitExceptionHandler implements UncaughtExceptionHandler {
 		throw new SilentExitException();
 	}
 
-	private static class SilentExitException extends RuntimeException {
+	private static final class SilentExitException extends RuntimeException {
 
 	}
 

spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/autoconfigure/DevToolsR2dbcAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -186,7 +186,7 @@ class DevToolsR2dbcAutoConfigurationTests {
 
 	}
 
-	private static class MockConnectionFactory implements ConnectionFactory {
+	private static final class MockConnectionFactory implements ConnectionFactory {
 
 		@Override
 		public Publisher<? extends Connection> create() {

spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/filewatch/FileSystemWatcherTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -326,7 +326,7 @@ class FileSystemWatcherTests {
 		return file;
 	}
 
-	private static class TestSnapshotStateRepository implements SnapshotStateRepository {
+	private static final class TestSnapshotStateRepository implements SnapshotStateRepository {
 
 		private Object state;
 

spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/RestartApplicationListenerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -127,7 +127,7 @@ class RestartApplicationListenerTests {
 		}
 	}
 
-	private static class ImplicitlyEnabledRestartApplicationListener extends RestartApplicationListener {
+	private static final class ImplicitlyEnabledRestartApplicationListener extends RestartApplicationListener {
 
 		@Override
 		boolean implicitlyEnableRestart() {

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/features/testing/utilities/testresttemplate/MySpringBootTestsConfiguration.java

@@ -34,7 +34,7 @@ import org.springframework.web.bind.annotation.RestController;
 public class MySpringBootTestsConfiguration {
 
 	@RestController
-	private static class ExampleController {
+	private static final class ExampleController {
 
 		@RequestMapping("/example")
 		ResponseEntity<String> example() {

spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/OverrideAutoConfigurationContextCustomizerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -51,7 +51,7 @@ class OverrideAutoConfigurationContextCustomizerFactory implements ContextCustom
 	/**
 	 * {@link ContextCustomizer} to disable full auto-configuration.
 	 */
-	private static class DisableAutoConfigurationContextCustomizer implements ContextCustomizer {
+	private static final class DisableAutoConfigurationContextCustomizer implements ContextCustomizer {
 
 		@Override
 		public void customizeContext(ConfigurableApplicationContext context, MergedContextConfiguration mergedConfig) {

spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/restdocs/RestDocsTestExecutionListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -56,7 +56,7 @@ public class RestDocsTestExecutionListener extends AbstractTestExecutionListener
 		}
 	}
 
-	private static class DocumentationHandler {
+	private static final class DocumentationHandler {
 
 		private void beforeTestMethod(TestContext testContext) {
 			ManualRestDocumentation restDocumentation = findManualRestDocumentation(testContext);

spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/servlet/SpringBootMockMvcBuilderCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -173,7 +173,7 @@ public class SpringBootMockMvcBuilderCustomizer implements MockMvcBuilderCustomi
 				writer.write(((Printer) getPrinter()).getLines());
 			}
 
-			private static class Printer implements ResultValuePrinter {
+			private static final class Printer implements ResultValuePrinter {
 
 				private final List<String> lines = new ArrayList<>();
 
@@ -257,7 +257,7 @@ public class SpringBootMockMvcBuilderCustomizer implements MockMvcBuilderCustomi
 	/**
 	 * {@link LinesWriter} to output results to the log.
 	 */
-	private static class LoggingLinesWriter implements LinesWriter {
+	private static final class LoggingLinesWriter implements LinesWriter {
 
 		private static final Log logger = LogFactory.getLog("org.springframework.test.web.servlet.result");
 
@@ -314,7 +314,7 @@ public class SpringBootMockMvcBuilderCustomizer implements MockMvcBuilderCustomi
 			addAsRegistrationBean(beanFactory, Filter.class, new FilterRegistrationBeanAdapter());
 		}
 
-		private static class FilterRegistrationBeanAdapter implements RegistrationBeanAdapter<Filter> {
+		private static final class FilterRegistrationBeanAdapter implements RegistrationBeanAdapter<Filter> {
 
 			@Override
 			public RegistrationBean createRegistrationBean(String name, Filter source, int totalNumberOfSourceBeans) {

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/context/SpringBootContextLoader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -380,7 +380,7 @@ public class SpringBootContextLoader extends AbstractContextLoader implements Ao
 	/**
 	 * Inner class to configure {@link WebMergedContextConfiguration}.
 	 */
-	private static class WebConfigurer {
+	private static final class WebConfigurer {
 
 		void configure(MergedContextConfiguration mergedConfig, List<ApplicationContextInitializer<?>> initializers) {
 			WebMergedContextConfiguration webMergedConfig = (WebMergedContextConfiguration) mergedConfig;

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/json/DuplicateJsonObjectContextCustomizerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -44,7 +44,7 @@ class DuplicateJsonObjectContextCustomizerFactory implements ContextCustomizerFa
 		return new DuplicateJsonObjectContextCustomizer();
 	}
 
-	private static class DuplicateJsonObjectContextCustomizer implements ContextCustomizer {
+	private static final class DuplicateJsonObjectContextCustomizer implements ContextCustomizer {
 
 		private final Log logger = LogFactory.getLog(DuplicateJsonObjectContextCustomizer.class);
 

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/mock/mockito/MockitoTestExecutionListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -121,7 +121,7 @@ public class MockitoTestExecutionListener extends AbstractTestExecutionListener
 	/**
 	 * {@link FieldCallback} to collect Mockito annotations.
 	 */
-	private static class MockitoAnnotationCollection implements FieldCallback {
+	private static final class MockitoAnnotationCollection implements FieldCallback {
 
 		private final Set<Annotation> annotations = new LinkedHashSet<>();
 

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/web/client/TestRestTemplate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -1077,7 +1077,7 @@ public class TestRestTemplate {
 
 	}
 
-	private static class NoOpResponseErrorHandler extends DefaultResponseErrorHandler {
+	private static final class NoOpResponseErrorHandler extends DefaultResponseErrorHandler {
 
 		@Override
 		public void handleError(ClientHttpResponse response) throws IOException {

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/SpringBootContextLoaderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -474,7 +474,8 @@ class SpringBootContextLoaderTests {
 
 	}
 
-	private static class ContextLoaderApplicationContextFailureProcessor implements ApplicationContextFailureProcessor {
+	private static final class ContextLoaderApplicationContextFailureProcessor
+			implements ApplicationContextFailureProcessor {
 
 		static ApplicationContext failedContext;
 

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/mock/mockito/SpringBootMockResolverTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -54,7 +54,7 @@ class SpringBootMockResolverTests {
 
 	}
 
-	private static class MyServiceImpl implements MyService {
+	private static final class MyServiceImpl implements MyService {
 
 		@Override
 		public int a() {

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/web/reactive/server/WebTestClientContextCustomizerWithoutWebfluxIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -45,7 +45,7 @@ class WebTestClientContextCustomizerWithoutWebfluxIntegrationTests {
 	}
 
 	@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
-	private static class TestClass {
+	private static final class TestClass {
 
 	}
 

spring-boot-project/spring-boot-testcontainers/src/test/java/org/springframework/boot/testcontainers/lifecycle/TestcontainersStartupTests.java

@@ -93,7 +93,7 @@ class TestcontainersStartupTests {
 		return testStartables;
 	}
 
-	private class TestStartable implements Startable {
+	private final class TestStartable implements Startable {
 
 		private int index;
 

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/BuildpackLayersMetadata.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -101,7 +101,7 @@ final class BuildpackLayersMetadata extends MappedObject {
 		return new BuildpackLayersMetadata(node);
 	}
 
-	private static class Buildpacks {
+	private static final class Buildpacks {
 
 		private final Map<String, BuildpackVersions> buildpacks = new HashMap<>();
 
@@ -126,7 +126,7 @@ final class BuildpackLayersMetadata extends MappedObject {
 
 	}
 
-	private static class BuildpackVersions {
+	private static final class BuildpackVersions {
 
 		private final Map<String, BuildpackLayerDetails> versions = new HashMap<>();
 

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/Lifecycle.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -331,7 +331,7 @@ class Lifecycle implements Closeable {
 	/**
 	 * Common directories used by the various phases.
 	 */
-	private static class Directory {
+	private static final class Directory {
 
 		/**
 		 * The directory used by buildpacks to write their layer contributions. A new

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/DockerApi.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -500,7 +500,7 @@ public class DockerApi {
 	/**
 	 * {@link UpdateListener} used to capture the image digest.
 	 */
-	private static class DigestCaptureUpdateListener implements UpdateListener<ProgressUpdateEvent> {
+	private static final class DigestCaptureUpdateListener implements UpdateListener<ProgressUpdateEvent> {
 
 		private static final String PREFIX = "Digest:";
 
@@ -521,7 +521,7 @@ public class DockerApi {
 	/**
 	 * {@link UpdateListener} used to ensure an image load response stream.
 	 */
-	private static class StreamCaptureUpdateListener implements UpdateListener<LoadImageUpdateEvent> {
+	private static final class StreamCaptureUpdateListener implements UpdateListener<LoadImageUpdateEvent> {
 
 		private String stream;
 
@@ -540,7 +540,7 @@ public class DockerApi {
 	 * {@link UpdateListener} used to capture the details of an error in a response
 	 * stream.
 	 */
-	private static class ErrorCaptureUpdateListener implements UpdateListener<PushImageUpdateEvent> {
+	private static final class ErrorCaptureUpdateListener implements UpdateListener<PushImageUpdateEvent> {
 
 		@Override
 		public void onUpdate(PushImageUpdateEvent event) {

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/transport/LocalHttpClientTransport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -88,7 +88,7 @@ final class LocalHttpClientTransport extends HttpClientTransport {
 	/**
 	 * {@link DnsResolver} that ensures only the loopback address is used.
 	 */
-	private static class LocalDnsResolver implements DnsResolver {
+	private static final class LocalDnsResolver implements DnsResolver {
 
 		private static final InetAddress LOOPBACK = InetAddress.getLoopbackAddress();
 
@@ -136,7 +136,7 @@ final class LocalHttpClientTransport extends HttpClientTransport {
 	/**
 	 * {@link HttpRoutePlanner} for local Docker.
 	 */
-	private static class LocalRoutePlanner implements HttpRoutePlanner {
+	private static final class LocalRoutePlanner implements HttpRoutePlanner {
 
 		@Override
 		public HttpRoute determineRoute(HttpHost target, HttpContext context) {

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/socket/DomainSocket.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -157,7 +157,7 @@ public abstract class DomainSocket extends AbstractSocket {
 	/**
 	 * {@link InputStream} returned from the {@link DomainSocket}.
 	 */
-	private class DomainSocketInputStream extends InputStream {
+	private final class DomainSocketInputStream extends InputStream {
 
 		@Override
 		public int read() throws IOException {
@@ -180,7 +180,7 @@ public abstract class DomainSocket extends AbstractSocket {
 	/**
 	 * {@link OutputStream} returned from the {@link DomainSocket}.
 	 */
-	private class DomainSocketOutputStream extends OutputStream {
+	private final class DomainSocketOutputStream extends OutputStream {
 
 		@Override
 		public void write(int b) throws IOException {