I just helped a customer who had a old jnlp applications that needed Java 5 and they had 5u22 and 7u51 installed.
They are running on Windows. I made a new desktop shortcut that uses the javaws from Java 5 like this: "path to java5\javaws" urltoJNLP.jnlp
Then it uses Webstart from Java 5.
I appreciate the tip on using a shortcut that specifies the path to a Java 5 or Java 6 WebStart.
However, it seems that the Java 6 Webstart launches the latest installed Java 7 process (ie.jre7\bin\javaw.exe) with various arguments set to the Java 6 jar files.
I see that the -Djnlpx.jvm argument also points to jre7\\bin\\javaw.exe.
Is there a setting (e.g. registry or such) that is causing the java 6 WebStart to use the java 7 javaw.exe process?
I confirm your findings when using shortcuts to try specific versions of JavaWS with 7u25 or later installed:
JRE 5u14 launched and the classloader was as pre 7u25
JRE 6u43 would not launch
JRE 7u21 launched but the classloader was not as pre 7u25
You can launch the shortcut with the JavaWS -verbose option to display a messagebox with valuable information.
I am keeping a close watch on this thread.