J2SE Version (please include all output from java -version flag):
java version "1.6.0_23"
Java(TM) SE Runtime Environment (build 1.6.0_23-b05)
Java HotSpot(TM) Client VM (build 19.0-b09, mixed mode, sharing)

Does this problem occur on J2SE 5.0.x or 6ux ? Yes / No (pick one)
Java 6ux


Operating System Configuration Information (be specific):
Windows XP
 with both IE 8 and Firefox 3.6

Bug Description:
Java Plugin: Loading applet-JARs with SSL and client authentication causes ConcurrentModificationException
.
It is a regression problem and occurs only with the next-generation java-plugin

Steps to Reproduce (be specific):

Deploy an applet on a site where access is restricted to ssl client authentication.
Launch the applet and watch the java console.

(check Comments field for detail)


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected Console Output
No error is logged

ACTUAL -
Actual Console Output
The console output starts with
Exception in thread "HandshakeCompletedNotify-Thread" java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
at java.util.HashMap$EntryIterator.next(Unknown Source)
at java.util.HashMap$EntryIterator.next(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl$NotifyHandshakeThread.run(Unknown Source)

This error appears after you choose your ssl client certificate in the java plugin client authentication dialog.

REPRODUCIBILITY :
This bug can be reproduced always.