diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowHttpHandlerAdapter.java b/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowHttpHandlerAdapter.java
index 3364a95493..8c58eb159d 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowHttpHandlerAdapter.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowHttpHandlerAdapter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2022 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 class UndertowHttpHandlerAdapter implements io.undertow.server.HttpHandle
 	}
 
 
-	private class HandlerResultSubscriber implements Subscriber<Void> {
+	private static class HandlerResultSubscriber implements Subscriber<Void> {
 
 		private final HttpServerExchange exchange;
 
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/VersionResourceResolver.java b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/VersionResourceResolver.java
index d923e96024..e945081b3c 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/VersionResourceResolver.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/VersionResourceResolver.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -236,7 +236,7 @@ public class VersionResourceResolver extends AbstractResourceResolver {
 	}
 
 
-	private class FileNameVersionedResource extends AbstractResource implements HttpResource {
+	private static class FileNameVersionedResource extends AbstractResource implements HttpResource {
 
 		private final Resource original;
 
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
index 973bbf4fb2..91e01527ee 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -82,7 +82,7 @@ public class UndertowRequestUpgradeStrategy implements RequestUpgradeStrategy {
 	}
 
 
-	private class DefaultCallback implements WebSocketConnectionCallback {
+	private static class DefaultCallback implements WebSocketConnectionCallback {
 
 		private final HandshakeInfo handshakeInfo;
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java
index f2469483ab..a3e1f140d7 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -232,7 +232,7 @@ public class VersionResourceResolver extends AbstractResourceResolver {
 	}
 
 
-	private class FileNameVersionedResource extends AbstractResource implements HttpResource {
+	private static class FileNameVersionedResource extends AbstractResource implements HttpResource {
 
 		private final Resource original;
 
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/XhrStreamingTransportHandler.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/XhrStreamingTransportHandler.java
index f947643205..2e8c3aea42 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/XhrStreamingTransportHandler.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/XhrStreamingTransportHandler.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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 @@ public class XhrStreamingTransportHandler extends AbstractHttpSendingTransportHa
 	}
 
 
-	private class XhrStreamingSockJsSession extends StreamingSockJsSession {
+	private static class XhrStreamingSockJsSession extends StreamingSockJsSession {
 
 		public XhrStreamingSockJsSession(String sessionId, SockJsServiceConfig config,
 				WebSocketHandler wsHandler, Map<String, Object> attributes) {