As Gili answered, you can use stub-files but, if you find a missing/incorrect annotation in the JDK, please report it to the Checker Framework mailing list checker-framework-discuss@googlegroups.com or report it as an issue in the issue tracker.
With each release, an Annotated JDK is bundled with the Checker Framework. It is used solely to retrieve annotations for common methods in the JDK. It is used automatically when you use the Checker Framework.
This annotation has been included since of Checker Framework release 1.8.0.