Retain original URL instance in case of custom URLStreamHandler

Closes gh-33199

Author: jhoeller

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

@@ -428,12 +428,18 @@ protected Resource convertClassLoaderURL(URL url) {
 			if (!cleanedPath.equals(urlString)) {
 				// Prefer cleaned URL, aligned with UrlResource#createRelative(String)
 				try {
-					return new UrlResource(ResourceUtils.toURI(cleanedPath));
+					// Cannot test for URLStreamHandler directly: URL equality for same String
+					// in order to find out whether original URL uses default URLStreamHandler.
+					if (ResourceUtils.toURL(urlString).equals(url)) {
+						// Plain URL with default URLStreamHandler -> replace with cleaned path.
+						return new UrlResource(ResourceUtils.toURI(cleanedPath));
+					}
 				}
 				catch (URISyntaxException | MalformedURLException ex) {
 					// Fallback to regular URL construction below...
 				}
 			}
+			// Retain original URL instance, potentially including custom URLStreamHandler.
 			return new UrlResource(url);
 		}
 	}