NetBeans update centre from local path

I have a Netbeans platform application and trying to implement autoupdate service,

So far am able to achieve updating from a URL by updating Bundle.properties and layer.xml

Like below,

Bundle.properties

Code:
update_center=file://xyz.com/NbUpdateCenter/updates.xml

......
......
Services/AutoupdateType/update_center.instance=Update Center



layer.xml

Code:
<folder name="Services">
        <folder name="AutoupdateType">
            <file name="update_center.instance">
                <attr name="displayName" bundlevalue="images.Bundle#Services/AutoupdateType/update_center.instance"/>
                <attr name="enabled" boolvalue="true"/>
                <attr name="instanceCreate" methodvalue="org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogFactory.createUpdateProvider"/>
                <attr name="instanceOf" stringvalue="org.netbeans.spi.autoupdate.UpdateProvider"/>
                <attr name="url" bundlevalue="images.Bundle#update_center"/>
            </file>
        </folder>
    </folder>



What i am trying to do is,

Keep the required files in local path and update from there.

Something like this,


Code:
update_center=file://C:/NbUpdateCenter/updates.xml



It throws , INFO [org.netbeans.modules.autoupdate.updateprovider.DownloadListener]: Reading URL file://C:/NbUpdateCenter/updates.xml failed (java.net.UnknownHostException: C)


Is it possible to update from local path if all required files are available. or how should i do this?