@Documented @Retention(value=RUNTIME) @InheritedAnnotation @Target(value={METHOD,CONSTRUCTOR}) public @interface LockingFree
synchronized, it contains no synchronized blocks,
 it contains no calls to lock or unlock, and it contains no calls to other
 non-@LockingFree methods.
 @LockingFree provides a stronger guarantee than @ReleasesNoLocks and a
 weaker guarantee than @SideEffectFree.
MayReleaseLocks, 
ReleasesNoLocks, 
SideEffectFree, 
Pure