FULL PRODUCT VERSION :
java version "1.7.0_03"
Java(TM) SE Runtime Environment (build 1.7.0_03-b05)
Java HotSpot(TM) Client VM (build 22.1-b02, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

EXTRA RELEVANT SYSTEM CONFIGURATION :
i tested it with an Apache Tomcat 6.0.35 and Firefox 12.0

A DESCRIPTION OF THE PROBLEM :
Loading an applet where the server is configured for client authentication causes a ClassNotFoundException for the applet class at least in firefox.

I tried all possible tags to define an applet (embed, applet, object), all of them leading to the same exception, where the class is not found. I also tried to load the class from an archive, with no success.

It just works, when i set the clientAuth attribute to "false" in the server.xml, so i guess it has something to do with client authentication.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Install an apache tomcat 6.0.35

2. configure the tomcat for client authentication

a. insert the following connector in the server.xml:
<Connector SSLEnabled="true" clientAuth="true" keystoreFile="ssl/keystore.jks" keystorePass="tomcat" maxThreads="150" port="8443" protocol="HTTP/1.1" scheme="https" secure="true" sslProtocol="TLS" truststoreFile="ssl/truststore.jks" truststorePass="tomcat"/>

here are my sample trust- and keystore + a sample client certificate:
https://github.com/spuckydaslama/bugreport.appletandclientauth/downloads

b. copy truststore.jks and keystore.jks to <tomcatinstallation>/ssl

c. import the tomcat.p12 into your firefox

3. Deploy/copy the following webapp the tomcat installation:
https://github.com/downloads/spuckydaslama/bugreport.appletandclientauth/appletandclientauth.zip

the webapp includes an index.html loading a simple applet which prints out a line on start.

4. start the server and browse to https://localhost:8443/appletandclientauth/


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The applet is started without exceptions.
ACTUAL -
An exception is thrown (see below) and the applet therefore cannot be started.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
network: Verbindung von https://localhost:8443/appletandclientauth/bugreport/appletandclientauth/SimpleApplet.class mit Proxy=DIRECT wird hergestellt
network: Verbindung von http://localhost:8443/ mit Proxy=DIRECT wird hergestellt
security: Zertifikate werden aus Deployment-Session-Zertifikatspeicher geladen
security: Zertifikate wurden aus Deployment-Session-Zertifikatspeicher geladen
security: Zertifikat wird im Zertifikatspeicher "Deployment denied" gesucht
security: Zertifikat wird in Deployment-Session-Zertifikatspeicher gesucht
network: Verbindung von https://localhost:8443/appletandclientauth/bugreport/appletandclientauth/SimpleApplet/class.class mit Proxy=DIRECT wird hergestellt
network: Verbindung von http://localhost:8443/ mit Proxy=DIRECT wird hergestellt
security: Zertifikate werden aus Deployment-Session-Zertifikatspeicher geladen
security: Zertifikate wurden aus Deployment-Session-Zertifikatspeicher geladen
security: Zertifikat wird im Zertifikatspeicher "Deployment denied" gesucht
security: Zertifikat wird in Deployment-Session-Zertifikatspeicher gesucht
java.lang.ClassNotFoundException: bugreport.appletandclientauth.SimpleApplet.class
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.initAppletAdapter(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
basic: Laden: Klasse bugreport.appletandclientauth.SimpleApplet.class nicht gefunden.
java.lang.ClassNotFoundException: bugreport.appletandclientauth.SimpleApplet.class
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.initAppletAdapter(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Ignored exception: java.lang.ClassNotFoundException: bugreport.appletandclientauth.SimpleApplet.class
basic: Fortschritts-Listener entfernt: sun.plugin.util.ProgressMonitorAdapter@dbd984
security: Speicher für abgelehnte Sessionzertifikate zurücksetzen


REPRODUCIBILITY :
This bug can be reproduced always.