Align with Servlet 6.0 and introduce support for Jakarta WebSocket 2.1

Includes corresponding build upgrade to Tomcat 10.1.1 and Undertow 2.3.0
(while retaining runtime compatibility with Tomcat 10.0 and Undertow 2.2)

Closes gh-29435
Closes gh-29436

spring-websocket/src/main/java/org/springframework/web/socket/server/standard/AbstractTyrusRequestUpgradeStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 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.
@@ -72,7 +72,7 @@ public abstract class AbstractTyrusRequestUpgradeStrategy extends AbstractStanda
 
 	private static final Constructor<?> constructor;
 
-	private static boolean constructorWithBooleanArgument;
+	private static final boolean constructorWithBooleanArgument;
 
 	private static final Method registerMethod;
 

spring-websocket/src/main/java/org/springframework/web/socket/server/standard/StandardWebSocketUpgradeStrategy.java

@@ -0,0 +1,77 @@
+/*
+ * 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.socket.server.standard;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jakarta.websocket.Endpoint;
+import jakarta.websocket.Extension;
+
+import org.springframework.http.server.ServerHttpRequest;
+import org.springframework.http.server.ServerHttpResponse;
+import org.springframework.lang.Nullable;
+import org.springframework.web.socket.server.HandshakeFailureException;
+
+/**
+ * A WebSocket {@code RequestUpgradeStrategy} for the Jakarta WebSocket API 2.1+.
+ *
+ * <p>To modify properties of the underlying {@link jakarta.websocket.server.ServerContainer}
+ * you can use {@link ServletServerContainerFactoryBean} in XML configuration or,
+ * when using Java configuration, access the container instance through the
+ * "jakarta.websocket.server.ServerContainer" ServletContext attribute.
+ *
+ * @author Juergen Hoeller
+ * @since 6.0
+ * @see jakarta.websocket.server.ServerContainer#upgradeHttpToWebSocket
+ */
+public class StandardWebSocketUpgradeStrategy extends AbstractStandardUpgradeStrategy {
+
+	@Override
+	public String[] getSupportedVersions() {
+		return new String[] {"13"};
+	}
+
+	@Override
+	public void upgradeInternal(ServerHttpRequest request, ServerHttpResponse response,
+			@Nullable String selectedProtocol, List<Extension> selectedExtensions, Endpoint endpoint)
+			throws HandshakeFailureException {
+
+		HttpServletRequest servletRequest = getHttpServletRequest(request);
+		HttpServletResponse servletResponse = getHttpServletResponse(response);
+
+		StringBuffer requestUrl = servletRequest.getRequestURL();
+		String path = servletRequest.getRequestURI();  // shouldn't matter
+		Map<String, String> pathParams = Collections.<String, String> emptyMap();
+
+		ServerEndpointRegistration endpointConfig = new ServerEndpointRegistration(path, endpoint);
+		endpointConfig.setSubprotocols(Collections.singletonList(selectedProtocol));
+		endpointConfig.setExtensions(selectedExtensions);
+
+		try {
+			getContainer(servletRequest).upgradeHttpToWebSocket(servletRequest, servletResponse, endpointConfig, pathParams);
+		}
+		catch (Exception ex) {
+			throw new HandshakeFailureException(
+					"Servlet request failed to upgrade to WebSocket: " + requestUrl, ex);
+		}
+	}
+
+}

spring-websocket/src/main/java/org/springframework/web/socket/server/standard/TomcatRequestUpgradeStrategy.java

@@ -42,6 +42,7 @@ import org.springframework.web.socket.server.HandshakeFailureException;
  *
  * @author Rossen Stoyanchev
  * @since 4.0
+ * @see WsServerContainer#upgradeHttpToWebSocket
  */
 public class TomcatRequestUpgradeStrategy extends AbstractStandardUpgradeStrategy {
 

spring-websocket/src/main/java/org/springframework/web/socket/server/support/AbstractHandshakeHandler.java

@@ -47,6 +47,7 @@ import org.springframework.web.socket.handler.WebSocketHandlerDecorator;
 import org.springframework.web.socket.server.HandshakeFailureException;
 import org.springframework.web.socket.server.HandshakeHandler;
 import org.springframework.web.socket.server.RequestUpgradeStrategy;
+import org.springframework.web.socket.server.standard.StandardWebSocketUpgradeStrategy;
 
 /**
  * A base class for {@link HandshakeHandler} implementations, independent of the Servlet API.
@@ -149,7 +150,8 @@ public abstract class AbstractHandshakeHandler implements HandshakeHandler, Life
 			className = "org.springframework.web.socket.server.standard.WebSphereRequestUpgradeStrategy";
 		}
 		else {
-			throw new IllegalStateException("No suitable default RequestUpgradeStrategy found");
+			// Let's assume Jakarta WebSocket API 2.1+
+			return new StandardWebSocketUpgradeStrategy();
 		}
 
 		try {