Is there any non-painful way to upgrade an Eclipse installation? I have tried browsing the eclipse site but I cannot find an useful description.
Add the update URL to your available sites:
Window > Preferences > Install/Update > Available Software Sites > Add...
Name: Oxygen
Location: http://download.eclipse.org/releases/oxygen/
Then tell Eclipse to look for updates: Help > Check for updates.
After the installation, Eclipse will restart and show the old splash screen. Next time you manually stop/start Eclipse it will correctly show the correct splash screen.