With the release of JDK 7 people have been asking “Where is JDK 7 for Mac OS X?”.
Apple and Oracle engineers are currently actively working on integrating the OS X Java code base into OpenJDK. This initial integration takes time and we can’t yet give you a specific date on the completion.
However, the integration is coming along well. You can check out the details of the Mac OS X Port Project within OpenJDK, see the status on the project wiki, and follow the mailing list. There are also regular (but unofficial) builds available for download.
PS: Of course, you can still always get the official Apple OS X JDK 6 implementation through the OS X “Software Update” mechanism.