Steps:
1. On a Vista machine.
2. Install jdk5 family u7 onwards any version.This is when we started the JavaPlugin.FamilyVersionSupport.
3. On that install any other higher version of 5 say 5u14.
4. Without the fix:The Key HKEY_CLASSES_ROOT\JavaPlugin.FamilyVersionSupport gets deleted.
Expected behaviour:This key should remain until the uninstallation of all the versions supporting the key.