Whenathreadatries toacquire a JUClock, whilethis lock hasbeenacquired by anotherthread, thenthread a has to "stop" its execution and wait until this lock is releasedortimes out.
Nadal misjudges a low forehand at the net to make it 30-30 and Murray then races in to thread a backhand winner up the line for 30-40 and break point .
Unique mastery of the craft is passed to young girls through years of informal exposure and then formal instruction by their mother or grandmother in applying cotton thread to linen.