FileUrlResource creates same class from createRelative

Issue: SPR-16140

spring-core/src/main/java/org/springframework/core/io/FileUrlResource.java

@@ -70,6 +70,14 @@ public class FileUrlResource extends UrlResource implements WritableResource {
 	}
 
 
+	@Override
+	public Resource createRelative(String relativePath) throws MalformedURLException {
+		if (relativePath.startsWith("/")) {
+			relativePath = relativePath.substring(1);
+		}
+		return new FileUrlResource(new URL(getURL(), relativePath));
+	}
+
 	@Override
 	public boolean isWritable() {
 		try {

spring-core/src/main/java/org/springframework/core/io/UrlResource.java

@@ -183,7 +183,7 @@ public class UrlResource extends AbstractFileResolvingResource {
 	 * This implementation returns the underlying URL reference.
 	 */
 	@Override
-	public URL getURL() throws IOException {
+	public URL getURL() {
 		return this.url;
 	}