Restore `Session.Cookie` class for binary back-compatibility

Fixes gh-38589

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/server/Session.java

@@ -23,7 +23,6 @@ import java.util.Set;
 
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 import org.springframework.boot.convert.DurationUnit;
-import org.springframework.boot.web.server.Cookie;
 
 /**
  * Session properties.
@@ -103,6 +102,15 @@ public class Session {
 		return this.sessionStoreDirectory;
 	}
 
+	/**
+	 * Session cookie properties. This class is provided only for back-compatibility
+	 * reasons, consider using {@link org.springframework.boot.web.server.Cookie} whever
+	 * possible.
+	 */
+	public static class Cookie extends org.springframework.boot.web.server.Cookie {
+
+	}
+
 	/**
 	 * Available session tracking modes (mirrors
 	 * {@link jakarta.servlet.SessionTrackingMode}.

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/SessionTests.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2012-2023 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.boot.web.servlet.server;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link Session}.
+ *
+ * @author Phillip Webb
+ */
+class SessionTests {
+
+	@Test // gh-38589
+	void getCookieIsBinaryBackCompatible() throws Exception {
+		Class<?> returnType = Session.class.getDeclaredMethod("getCookie").getReturnType();
+		assertThat(returnType.getName()).isEqualTo("org.springframework.boot.web.servlet.server.Session$Cookie");
+	}
+
+}