I see that the above annotations are used extensively in the book JCIP . I think it is really useful because even in the absence of proper documentation it says some things about the synchronization policies . I also see that Intellij Idea makes use of these annotations Are they now actually part of the Java language itself ?
assylias
These are custom annotations that are not part of the standard JDK. To be able to use them in your code, you need to add a dependency.
At jcip.net, there is a link to the library and its source in the bottom part of the page "Concurrency annotations: jar, javadoc, source".
Direct links:
来源：https://stackoverflow.com/questions/11362298/guardedby-threadsafe-notthreadsafe