I have a solution that has worked on 2 macs-an iMac and a macbook pro-both that were upgraded to mavericks. I got the help of a very smart person. his diagnosis was that there was interaction between Java 6 and 7 that was not a problem with 10.8.5 but having both is a problem with mavericks. my guess is that you previously installed Java 7 on top of Java 6, which was true for me.
so, we eliminated all java files we could find, uninstalled Java 7, rebooted, flushed caches and reinstalled Java 7.
here are the specific steps:
-- /library/preferencepanes there is a file called "JavaControlPanel.prefPane" move that to trash
--/library/ move the Java folder to the trash
--/library/ move the Oracle folder to the trash
--uninstall JRE 7.45
you can do this by finding "JavaAppletPlugin.plugin" and moving it to the trash. that file is in /library/internet plug-ins. described here:
http://www.java.com/en/download/help/mac_uninstall_java.xml
--restarted and booted in safe mode (hold down the shift key during restart)
http://support.apple.com/kb/ht1564
--once safe boot was finished I logged back in and installed JRE-7u45
at that point the Java control panel was back to working normally. You can adjust the security slider and the "enable Java content in the browser" will be checked.
I do not know whether all these steps are required. I do know that this procedure has restored Java 7 functionality to my machines.
hopefully Oracle will release a revised Java 7 that removes the offending files as part of its installation.
if you follow these steps, let me know the outcome.
good luck!
pete