FULL PRODUCT VERSION :
java version "1.6.0_32"
Java(TM) SE Runtime Environment (build 1.6.0_32-b05)
Java HotSpot(TM) 64-Bit Server VM (build 20.7-b02, mixed mode)

and

java version "1.7.0_04"
Java(TM) SE Runtime Environment (build 1.7.0_04-b22)
Java HotSpot(TM) 64-Bit Server VM (build 23.0-b21, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601

A DESCRIPTION OF THE PROBLEM :
After download and running an Webstart-Application with Java 6, the application is listed in Java 6 Cache Viewer. If you now call Java 7 Cache Viewer you can see the application in Java 7 Cache Viewer. If you now call Java 6 Cache Viewer again, Java 6 Cache Viewer is empty. If you now call Java 7 Cache Viewer also again, Java 7 Cache Viewer is empty too.

REGRESSION. Last worked in version 7

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
- run Webstart-Application with Java 6
- start java 7 Cache Viewer (now Java 6 cache is damaged)
- start java 6 Cache Viewer (now Java 7 cache is damaged)

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
downloaded applications listed in both Cache Viewers, if necessary with independent redundant cache directories
ACTUAL -
Cache Viewers damage each other

ERROR MESSAGES/STACK TRACES THAT OCCUR :
no error message

REPRODUCIBILITY :
This bug can be reproduced always.