Clarified VfsResource constructor

Issue: SPR-17563

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

@@ -28,9 +28,9 @@ import org.springframework.util.Assert;
 /**
  * JBoss VFS based {@link Resource} implementation.
  *
- * <p>As of Spring 4.0, this class supports VFS 3.x on JBoss AS 6+ (package
- * {@code org.jboss.vfs}) and is in particular compatible with JBoss AS 7 and
- * WildFly 8.
+ * <p>As of Spring 4.0, this class supports VFS 3.x on JBoss AS 6+
+ * (package {@code org.jboss.vfs}) and is in particular compatible with
+ * JBoss AS 7 and WildFly 8+.
  *
  * @author Ales Justin
  * @author Juergen Hoeller
@@ -44,6 +44,11 @@ public class VfsResource extends AbstractResource {
 	private final Object resource;
 
 
+	/**
+	 * Create a new {@code VfsResource} wrapping the given resource handle.
+	 * @param resource a {@code org.jboss.vfs.VirtualFile} instance
+	 * (untyped in order to avoid a static dependency on the VFS API)
+	 */
 	public VfsResource(Object resource) {
 		Assert.notNull(resource, "VirtualFile must not be null");
 		this.resource = resource;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -31,9 +31,9 @@ import org.springframework.util.ReflectionUtils;
 /**
  * Utility for detecting and accessing JBoss VFS in the classpath.
  *
- * <p>As of Spring 4.0, this class supports VFS 3.x on JBoss AS 6+ (package
- * {@code org.jboss.vfs}) and is in particular compatible with JBoss AS 7 and
- * WildFly 8.
+ * <p>As of Spring 4.0, this class supports VFS 3.x on JBoss AS 6+
+ * (package {@code org.jboss.vfs}) and is in particular compatible with
+ * JBoss AS 7 and WildFly 8+.
  *
  * <p>Thanks go to Marius Bogoevici for the initial patch.
  * <b>Note:</b> This is an internal class and should not be used outside the framework.
@@ -58,13 +58,13 @@ public abstract class VfsUtils {
 	private static final Method VIRTUAL_FILE_METHOD_TO_URI;
 	private static final Method VIRTUAL_FILE_METHOD_GET_NAME;
 	private static final Method VIRTUAL_FILE_METHOD_GET_PATH_NAME;
+	private static final Method VIRTUAL_FILE_METHOD_GET_PHYSICAL_FILE;
 	private static final Method VIRTUAL_FILE_METHOD_GET_CHILD;
 
 	protected static final Class<?> VIRTUAL_FILE_VISITOR_INTERFACE;
 	protected static final Method VIRTUAL_FILE_METHOD_VISIT;
 
 	private static final Field VISITOR_ATTRIBUTES_FIELD_RECURSE;
-	private static final Method GET_PHYSICAL_FILE;
 
 	static {
 		ClassLoader loader = VfsUtils.class.getClassLoader();
@@ -82,7 +82,7 @@ public abstract class VfsUtils {
 			VIRTUAL_FILE_METHOD_TO_URL = virtualFile.getMethod("toURL");
 			VIRTUAL_FILE_METHOD_GET_NAME = virtualFile.getMethod("getName");
 			VIRTUAL_FILE_METHOD_GET_PATH_NAME = virtualFile.getMethod("getPathName");
-			GET_PHYSICAL_FILE = virtualFile.getMethod("getPhysicalFile");
+			VIRTUAL_FILE_METHOD_GET_PHYSICAL_FILE = virtualFile.getMethod("getPhysicalFile");
 			VIRTUAL_FILE_METHOD_GET_CHILD = virtualFile.getMethod("getChild", String.class);
 
 			VIRTUAL_FILE_VISITOR_INTERFACE = loader.loadClass(VFS3_PKG + "VirtualFileVisitor");
@@ -125,7 +125,7 @@ public abstract class VfsUtils {
 
 	static boolean isReadable(Object vfsResource) {
 		try {
-			return ((Long) invokeVfsMethod(VIRTUAL_FILE_METHOD_GET_SIZE, vfsResource) > 0);
+			return (Long) invokeVfsMethod(VIRTUAL_FILE_METHOD_GET_SIZE, vfsResource) > 0;
 		}
 		catch (IOException ex) {
 			return false;
@@ -170,7 +170,7 @@ public abstract class VfsUtils {
 	}
 
 	static File getFile(Object vfsResource) throws IOException {
-		return (File) invokeVfsMethod(GET_PHYSICAL_FILE, vfsResource);
+		return (File) invokeVfsMethod(VIRTUAL_FILE_METHOD_GET_PHYSICAL_FILE, vfsResource);
 	}
 
 	static Object getRoot(URI url) throws IOException {