FULL PRODUCT VERSION :
java version " 1.6.0_45 "
Java(TM) SE Runtime Environment (build 1.6.0_45-b06)
Java HotSpot(TM) Client VM (build 20.45-b01, mixed mode, sharing)

java version " 1.7.0_21 "
Java(TM) SE Runtime Environment (build 1.7.0_21-b11)
Java HotSpot(TM) 64-Bit Server VM (build 23.21-b01, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601] with 64-bit

EXTRA RELEVANT SYSTEM CONFIGURATION :
Java 6 Update 45 (32-bit and 64-bit) JRE installed, Java 7 Update 21 (32-Bit and 64-Bit) installed

A DESCRIPTION OF THE PROBLEM :
Application requires Java 6, since it is not yet compatible to Java 7. Updates of customer base in progress but requires time.
After installing JRE 7u21 (32-Bit) The application can't start via WebStart anymore. Java WebStart requires start of most recent Java version, which is Java 7. Application can't run in Java 7, so it's broken now. Application is an ERP, which is business critical. Not good for Java!

REGRESSION. Last worked in version 7u17

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
On Window 7 (64-Bit) install Java 6u43 (32-Bit), Java 7u17 (32-Bit) and create a JNLP that only allows Java 6. Application will launch.
Then install Java 7u21 (32-Bit) and try to launch JNLP

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Java Webstart should allow to start applications with the required Java version, if one is installed. Business critical application, that rely for almost a decade on WebStart for deployment must not be broken over night. Customers need to be able to use most recent and secure Java 7 but also run their business critical application.
ACTUAL -
JNLP application that need Java 6 can't start anymore.

The Error message below is wrong: It states " Es wird empfohlen " which means " It is recommended " . What happens is, that it requires a new Java Major Version. But there are lots of applications not ready for Java 7 out in production.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Warnung - Nicht verf?gbare Java-Version angefordert

Diese Anwendung m?chte eine Version von Java (1.6) verwenden, die von Ihren Sicherheitseinstellungen blockiert wird. Es wird empfohlen, dass Sie die Anwendung mit der neuesten Version von Java auf Ihrem Rechner ausf?hren.
[Mit der neuesten Version ausf?hren] [Abbrechen]


REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
Not using the most recent and secure Java. Java 7u21 must be uninstalled. PC is not any more secure, than before, though an new Java is out. This makes things worse instead of better.