Getting ConcurrentModificationException when the non-existent proxy is used

Tested build : 6U10 b08
Tested OS : windows
Steps to reproduce :
1. Install jre bundle
2. launch java control panel
3. Choose General->NetworkSettings->Use Proxy Server
4. Set the proxy as scaweb.sfbay.sun.com and port as 8080 (or any proxy which does not exist) and click apply
5. Launch any browser and try to launch any applet from java.sun.com site
In console, it throws java.util.ConcurrentModificationException instead of ClassNotFoundException
This happens from 6U10 b08. Till 6U10 b07, it is giving ClassNotFoundException.

plugin.trace file attached