question: private void writeObject ( java . io . ObjectOutputStream s ) throws java . io . IOException { final ReentrantLock lock = this . lock ; lock . lock ( ) ; try { s . defaultWriteObject ( ) ; for ( Node < E > p = first ; p != null ; p = p . next ) s . writeObject ( p . item ) ; s . writeObject ( null ) ; } finally { lock . unlock ( ) ; } }
target:  Saves this deque to a stream (that is, serializes it).