--- old/src/java.base/share/classes/java/nio/file/FileSystems.java	2017-04-22 21:31:17.495179924 +0200
+++ new/src/java.base/share/classes/java/nio/file/FileSystems.java	2017-04-22 21:31:17.411181374 +0200
@@ -145,6 +145,15 @@
     }
 
     /**
+     * Returns the builtin {@code FileSystem}.
+     *
+     * @return the builtin file system
+     */
+    static FileSystem getBuiltin() {
+        return BuiltinFileSystemHolder.builtinFileSystem;
+    }
+
+    /**
      * Returns the default {@code FileSystem}. The default file system creates
      * objects that provide access to the file systems accessible to the Java
      * virtual machine. The <em>working directory</em> of the file system is
--- old/src/java.base/share/classes/java/nio/file/Path.java	2017-04-22 21:31:17.757175404 +0200
+++ new/src/java.base/share/classes/java/nio/file/Path.java	2017-04-22 21:31:17.680176732 +0200
@@ -652,7 +652,8 @@
      *          if this {@code Path} is not associated with the default provider
      */
     default File toFile() {
-        if (getFileSystem() == FileSystems.getDefault()) {
+        if (getFileSystem() == FileSystems.getBuiltin() ||
+            getFileSystem() == FileSystems.getDefault()) {
             return new File(toString());
         } else {
             throw new UnsupportedOperationException("Path not associated with "