question: public void clear ( ) { final ReentrantLock lock = this . lock ; lock . lock ( ) ; try { for ( Node < E > f = first ; f != null ; ) { f . item = null ; Node < E > n = f . next ; f . prev = null ; f . next = null ; f = n ; } first = last = null ; count = 0 ; notFull . signalAll ( ) ; } finally { lock . unlock ( ) ; } }
target:  Atomically removes all of the elements from this deque. The deque will be empty after this call returns.