This problem has been observed on several Linux systems, it is most common on Java Desktop System 2 but has also been observed on Red Hat distributions.
After clicking the "Start Upgrade Tool" button on the final installer screen, the installer fails to launch the upgrade tool to complete the upgrade process, and hangs indefinitely, not returning the command prompt.
This issue is not encountered if command line installation mode is used to run upgrade in place.
If you ran upgrade in place in GUI mode and encountered this problem, exit the installer by pressing Ctrl+C in the terminal window in which the installer was started.
Start upgrade tool from the terminal window, using following command:
as-install/bin/asupgrade --source as-install/domains --target as-install --adminuser adminuser --adminpassword adminpassword --masterpassword changeit
adminuser and adminpassword should match the values used for the installation you are upgrading.
When the upgrade tool completes the upgrade process you can also start the browser and enter following URL in order to review About page:
If you also selected the installation option to register the product, follow the link to registration page available on product About page.