From ce2689eead26c73603455d33a30fb1822bc93d25 Mon Sep 17 00:00:00 2001
From: Juergen Hoeller <hoellerj@vmware.com>
Date: Tue, 28 Mar 2023 13:20:49 +0200
Subject: [PATCH] Use MethodInvocationInfo class loader in case of core JDK
 interface type

Closes gh-30210
---
 .../annotation/MvcUriComponentsBuilder.java   |  9 +++--
 .../MvcUriComponentsBuilderTests.java         | 33 +++++++++++++------
 2 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilder.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilder.java
index 34636e1b9f..c4d2b96af6 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilder.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilder.java
@@ -779,9 +779,12 @@ public class MvcUriComponentsBuilder {
 			}
 
 			else if (controllerType.isInterface()) {
-				return (T) Proxy.newProxyInstance(controllerType.getClassLoader(),
-						new Class<?>[] {controllerType, MethodInvocationInfo.class},
-						interceptor);
+				ClassLoader classLoader = controllerType.getClassLoader();
+				if (classLoader == null) {  // JDK interface type from bootstrap loader
+					classLoader = MethodInvocationInfo.class.getClassLoader();
+				}
+				Class<?>[] ifcs = new Class<?>[] {controllerType, MethodInvocationInfo.class};
+				return (T) Proxy.newProxyInstance(classLoader, ifcs, interceptor);
 			}
 
 			else {
diff --git a/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilderTests.java b/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilderTests.java
index f772da13ab..04f341ee32 100644
--- a/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilderTests.java
+++ b/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilderTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * 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.
@@ -240,7 +240,7 @@ public class MvcUriComponentsBuilderTests {
 		assertThat(uriComponents.toUriString()).isEqualTo("http://localhost/");
 	}
 
-	@Test // gh-29897
+	@Test  // gh-29897
 	public void fromMethodNameInUnmappedControllerMethod() {
 		UriComponents uriComponents = fromMethodName(UnmappedControllerMethod.class, "getMethod").build();
 
@@ -384,7 +384,15 @@ public class MvcUriComponentsBuilderTests {
 		assertThat(uriComponents.encode().toUri().toString()).isEqualTo("http://localhost/hotels/42/bookings/21");
 	}
 
-	@Test // SPR-16710
+	@Test  // SPR-16710
+	public void fromMethodCallWithCharSequenceReturnType() {
+		UriComponents uriComponents = fromMethodCall(
+				on(BookingControllerWithCharSequence.class).getBooking(21L)).buildAndExpand(42);
+
+		assertThat(uriComponents.encode().toUri().toString()).isEqualTo("http://localhost/hotels/42/bookings/21");
+	}
+
+	@Test  // SPR-16710
 	public void fromMethodCallWithStringReturnType() {
 		assertThatIllegalStateException().isThrownBy(() -> {
 				UriComponents uriComponents = fromMethodCall(
@@ -403,7 +411,6 @@ public class MvcUriComponentsBuilderTests {
 
 	@Test
 	public void fromMappingNamePlain() {
-
 		initWebApplicationContext(WebConfig.class);
 
 		this.request.setServerName("example.org");
@@ -417,7 +424,6 @@ public class MvcUriComponentsBuilderTests {
 
 	@Test
 	public void fromMappingNameWithCustomBaseUrl() {
-
 		initWebApplicationContext(WebConfig.class);
 
 		UriComponentsBuilder baseUrl = UriComponentsBuilder.fromUriString("https://example.org:9999/base");
@@ -426,9 +432,8 @@ public class MvcUriComponentsBuilderTests {
 		assertThat(url).isEqualTo("https://example.org:9999/base/people/123/addresses/DE");
 	}
 
-	@Test // SPR-17027
+	@Test  // SPR-17027
 	public void fromMappingNameWithEncoding() {
-
 		initWebApplicationContext(WebConfig.class);
 
 		this.request.setServerName("example.org");
@@ -442,7 +447,6 @@ public class MvcUriComponentsBuilderTests {
 
 	@Test
 	public void fromMappingNameWithPathWithoutLeadingSlash() {
-
 		initWebApplicationContext(PathWithoutLeadingSlashConfig.class);
 
 		this.request.setServerName("example.org");
@@ -456,7 +460,6 @@ public class MvcUriComponentsBuilderTests {
 
 	@Test
 	public void fromControllerWithPrefix() {
-
 		initWebApplicationContext(PathPrefixWebConfig.class);
 
 		this.request.setScheme("https");
@@ -470,7 +473,6 @@ public class MvcUriComponentsBuilderTests {
 
 	@Test
 	public void fromMethodWithPrefix() {
-
 		initWebApplicationContext(PathPrefixWebConfig.class);
 
 		this.request.setScheme("https");
@@ -714,6 +716,17 @@ public class MvcUriComponentsBuilderTests {
 	}
 
 
+	@Controller
+	@RequestMapping("/hotels/{hotel}")
+	static class BookingControllerWithCharSequence {
+
+		@GetMapping("/bookings/{booking}")
+		public CharSequence getBooking(@PathVariable Long booking) {
+			return "url";
+		}
+	}
+
+
 	@Controller
 	@RequestMapping("/hotels/{hotel}")
 	static class BookingControllerWithString {