I bought OS X Mountain Lion from the App Store today (previously on Lion 10.7.4) and it downloaded and installed itself apparently without issue. However, when I checked back on my machine (Mid 2011 MacBook Pro) after letting it boot up properly I had a message telling me that I needed to install the Java SE 6 Runtime environment - so, I click yes and wait for it to find and install the software, only for it to fail and complain that the software is currently unavailable.
I've tried using the Applications > Utilities > Java Preferences application; I've tried going in to the terminal and typing 'java -v'; I've tried rebooting (and shutting down, then turning back on again); I've tried using Disk Utility to verify the disk - all to no avail: I keep getting the same outcome. I've had a look on the Java website to see if I could get the software there, but it just tells me to use the Apple Software Update feature. Sadly, I can't use the Software Update feature, as it takes me to the Mac App Store now (which doesn't work either, as it complains about being unable to verify its connection with itself).
Anyone got any clue how to solve this? I've looked at other threads here and also browsed other sites, but the only solutions suggested were the ones I listed above.