and then the package will see no java when it gets ready to install and it will fail.
This somewhat depends on which package of JRE8 you're using to do the installation. If you are using the *upgrade* package, then the absence of JRE7 would certainly be problematic.
But if you're using the *FULL* installer package, then the presence or absence of JRE7 is irrelevant.
But, there's actually a stronger reason why you should do the uninstallation of JRE7 after the *successful* installation of JRE8...
If you were to uninstall, or attempt to uninstall, JRE7 before installation JRE8, three undesirable scenarios could occur:
- The uninstall of JRE7 fails and the install of JRE8 fails, leaving the computer with no working JRE.
- The uninstall of JRE7 succeeds and the install of JRE8 fails, leaving the computer with no working JRE.
- The uninstall of JRE7 fails and the install of JRE8 succeeds, leaving you with a JRE7 mess to clean up, and hopefully a working JRE8.
Ergo, whether you do it via the package, or via a separate task, the uninstallation of the previous version should always succeed the successful installation of the newer version.