Please refer the following blog:https://blogs.oracle.com/stevenChan/entry/jre_7_certified_with_oracle
Clearly explains you about Coexistence of JRE 6 and JRE 7 on Windows desktops . Hope this ingformation help.
-Chiranjeevi M A
You can install both Java Version in your client machine and forms will be invoked from Java7.
Try by enabling java debug under the control panel and open the form... verify the invoked JRE Version.