javax.jnlp.DownloadService2 not detecting jar updates

FULL PRODUCT VERSION :
java version "1.7.0_60"
Java(TM) SE Runtime Environment (build 1.7.0_60-b19)
Java HotSpot(TM) Client VM (build 24.60-b09, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [version 5.1.2600]

EXTRA RELEVANT SYSTEM CONFIGURATION :
related to 6897140

A DESCRIPTION OF THE PROBLEM :
the method getUpdateAvailableResources() is used to check if an update of the resources is available on the server.

The server's jar are updated while the application is running.

subsecent calls to getUpdateAvailableResources() with a null argument for version (jars are not versioned) return an empty array instead of a non empty one.

as stated in bug 6897140, DownloadService2.getUpdateAvailableResources() should check timestamps of non versioned jars when a null version argument is provided. but it doesn't

REGRESSION. Last worked in version 6u43

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
-run a jnlp application throug a webserver, webstart will load the jars to the cache and then start the application
-update server's jars
-perform check on the available update using getUpdateAvailableResources() with a null version argument.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
getUpdateAvailableResources() should return a list of the updated jars
ACTUAL -
getUpdateAvailableResources() return an empty array.
Using wireshark, we saw that no http request is performed to check the server for updates.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
no error provided

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
DownloadService2 service = (DownloadService2) ServiceManager.lookup("javax.jnlp.DownloadService2");

if (service.getUpdateAvailableResources(new ResourceSpec("127.0.0.1" + "/.*", null, DownloadService2.ALL)).length != 0) {
     System.out.println("Update available");


---------- END SOURCE ----------