DOCS-915 clarifying example

Author: Sam Kleinman

source/applications/gridfs.txt

@@ -211,17 +211,18 @@ The following is an example of the GridFS interface in Java. The example
 is for demonstration purposes only. For API specifics, see the relevant
 :doc:`driver </applications/drivers>` documentation.
 
+By default, the interface must support the default GridFS bucket, named
+``fs``, as in the following: 
+
 .. code-block:: java
 
-   /*
-    * default root collection usage - must be supported
-    */
-   GridFS myFS = new GridFS(myDatabase);            // returns a default GridFS (e.g. "fs" bucket collection)
-   myFS.storeFile(new File("/tmp/largething.mpg")); // saves the file into the "fs" GridFS store
+   GridFS myFS = new GridFS(myDatabase); // returns default GridFS bucket (e.g. "fs"  collection)
+   myFS.storeFile(new File("/tmp/largething.mpg")); // saves the file to "fs" GridFS bucket
+
+Optionally, interfaces may support other additional GridFS buckets as
+in the following example: 
 
-   /*
-    * specified root collection usage - optional
-    */
+.. code-block:: java
 
-   GridFS myContracts = new GridFS(myDatabase, "contracts");            // returns a GridFS where  "contracts" is root
-   myFS.retrieveFile("smithco", new File("/tmp/smithco_20090105.pdf")); // retrieves object whose filename is "smithco"
+   GridFS myContracts = new GridFS(myDatabase, "contracts"); // returns GridFS bucket named "contracts" 
+   myFS.retrieveFile("smithco", new File("/tmp/smithco.pdf")); // retrieve GridFS object "smithco"