Try the following:
Install Java 7, and point both the application to manually use Java 7. It works fine for me. After java installation set the following in the client machine enviornmental variable:
Name = JAVA_TOOL_OPTIONS
Value = -Djava.vendor="Sun Microsystems Inc."
Hope this helps!
Thank you for your response. Unfortunately some of the applications will have to remain on Java 6. There are quite a few different applications we use and some of these are not yet certified with Java 7. Also, if we try to get them to work with Java 7 we'll have to go through full testing of all these applications. It will be far better if we can just install both versions of Java, which we know can be done. So it is just a question whether the order of install matters.
From previous experience installing the new 7 first will be set to default. and than when you install the 6 put it in a different area like for example c:\java6 or something similar and than for your appliacations that need the 6 have it point to that 6 location and you should be good for both. hope this helps!