Enforce cleaned URL for root resource from ClassLoader

Closes gh-32828

Author: jhoeller

spring-core/src/main/java/org/springframework/core/io/support/PathMatchingResourcePatternResolver.java

@@ -423,6 +423,17 @@ protected Resource convertClassLoaderURL(URL url) {
 			}
 		}
 		else {
+			String urlString = url.toString();
+			String cleanedPath = StringUtils.cleanPath(urlString);
+			if (!cleanedPath.equals(urlString)) {
+				// Prefer cleaned URL, aligned with UrlResource#createRelative(String)
+				try {
+					return new UrlResource(ResourceUtils.toURI(cleanedPath));
+				}
+				catch (URISyntaxException | MalformedURLException ex) {
+					// Fallback to regular URL construction below...
+				}
+			}
 			return new UrlResource(url);
 		}
 	}