Use MethodInvocationInfo class loader in case of core JDK interface type

Closes gh-30210

(cherry picked from commit ce2689e)

Author: jhoeller

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilder.java

@@ -776,9 +776,12 @@ private static <T> T initProxy(
 			}
 
 			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 {

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 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.
@@ -378,7 +378,15 @@ public void fromMethodCallWithObjectReturnType() {
 		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(
@@ -397,7 +405,6 @@ public void fromMethodNameWithStringReturnType() {
 
 	@Test
 	public void fromMappingNamePlain() {
-
 		initWebApplicationContext(WebConfig.class);
 
 		this.request.setServerName("example.org");
@@ -411,7 +418,6 @@ public void fromMappingNamePlain() {
 
 	@Test
 	public void fromMappingNameWithCustomBaseUrl() {
-
 		initWebApplicationContext(WebConfig.class);
 
 		UriComponentsBuilder baseUrl = UriComponentsBuilder.fromUriString("https://example.org:9999/base");
@@ -420,9 +426,8 @@ public void fromMappingNameWithCustomBaseUrl() {
 		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");
@@ -436,7 +441,6 @@ public void fromMappingNameWithEncoding() {
 
 	@Test
 	public void fromMappingNameWithPathWithoutLeadingSlash() {
-
 		initWebApplicationContext(PathWithoutLeadingSlashConfig.class);
 
 		this.request.setServerName("example.org");
@@ -450,7 +454,6 @@ public void fromMappingNameWithPathWithoutLeadingSlash() {
 
 	@Test
 	public void fromControllerWithPrefix() {
-
 		initWebApplicationContext(PathPrefixWebConfig.class);
 
 		this.request.setScheme("https");
@@ -463,7 +466,6 @@ public void fromControllerWithPrefix() {
 
 	@Test
 	public void fromMethodWithPrefix() {
-
 		initWebApplicationContext(PathPrefixWebConfig.class);
 
 		this.request.setScheme("https");
@@ -691,6 +693,17 @@ public Object getBooking(@PathVariable Long booking) {
 	}
 
 
+	@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 {