Have a Mac Mini running that had this problem under OSX 10.8 and is persisting in 10.9. When this computers reaches the self-provisioning portal, after clicking submit on the MAC address registration, the following screen displays an erroneous error that Java isn't installed.
Have gone through updating Java from Apple (2013-005) as well as from Oracle/Java (1.7), and applied several variations of uninstalling and reinstalling Java, doesn't seem to make a difference. From the top, the Mac Mini attaches to Wifi and the self-provisioning page appears with an authentication request. User authenticates succesfully. The next page displays the MAC address for the machine and a description field. Upon filling out the description, the page is submitted. The following page tha should complete the provisioning process, rather, displays an error that Java isn't installed and the user should go to java.com to complete the installation. According to the Java.com, Java is installed. According to terminal (by executing the command "java -version"), Java is installed. Running other Java applications, like JDE, run perfectly well. The self-provisioning page seems to be unaware of Java despite everything else. Ideas?