question: private void unparkSuccessor ( Node node ) { int ws = node . waitStatus ; if ( ws < 0 ) compareAndSetWaitStatus ( node , ws , 0 ) ; Node s = node . next ; if ( s == null || s . waitStatus > 0 ) { s = null ; for ( Node t = tail ; t != null && t != node ; t = t . prev ) if ( t . waitStatus <= 0 ) s = t ; } if ( s != null ) LockSupport . unpark ( s . thread ) ; }
target:  Wakes up node's successor, if one exists.