From what I've found online, this is a bug introduced in JDK 1.7.0_45. It appears to also be present in JDK 1.7.0_60. A bug report on Oracle's website states that, while there was a fix, it was removed before the JDK was released. I do not know why the fix was removed, but it confirms what we've already suspected -- the JDK is still broken.
The bug report claims that the error is benign and should not cause any run-time problems, though one of the comments disagrees with that. In my own experience, I have been able to work without any problems using JDK 1.7.0_60 despite seeing the message.
If this issue is causing serious problems, here are a few things I would suggest:
Revert back to JDK 1.7.0_25 until a fix is added to the JDK.
Keep an eye on the bug report so that you are aware of any work being done on this issue. Maybe even add your own comment so Oracle is aware of the severity of the issue.
Try the JDK early releases as they come out. One of them might fix your problem.
Instructions for installing the JDK on Mac OS X are available at JDK 7 Installation for Mac OS X. It also contains instructions for removing the JDK.
