Resource.isFile() and JAF MediaTypeFactory

Issue: SPR-14484

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/GzipResourceResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -103,6 +103,11 @@ public class GzipResourceResolver extends AbstractResourceResolver {
 			return this.gzipped.isOpen();
 		}
 
+		@Override
+		public boolean isFile() {
+			return this.gzipped.isFile();
+		}
+
 		public URL getURL() throws IOException {
 			return this.gzipped.getURL();
 		}

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java

@@ -264,6 +264,11 @@ public class VersionResourceResolver extends AbstractResourceResolver {
 			return this.original.isOpen();
 		}
 
+		@Override
+		public boolean isFile() {
+			return this.original.isFile();
+		}
+
 		@Override
 		public URL getURL() throws IOException {
 			return this.original.getURL();