private E unlinkLast ( Node < E > l ) { // assert l == last && l != null; final E element = l . item ; final Node < E > prev = l . prev ; l . item = null ; l . prev = null ; // help GC last = prev ; if ( prev == null ) first = null ; else prev . next = null ; size -- ; modCount ++ ; return element ; }
Unlinks non - null last node l .