public V remove(A arg){
  Future<V> future=cache.remove(arg);
  V res=null;
  if (future != null) {
    try {
      res=future.get();
    }
 catch (    InterruptedException|ExecutionException ignore) {
    }
  }
  return res;
}

public V remove ( A arg ) { Future < V > future = cache . remove ( arg ) ; V res = null ; if ( future != null ) { try { res = future . get ( ) ; } catch ( InterruptedException | ExecutionException ignore ) { } } return res ; }
removes the value to which the specified key is mapped , or null otherwise . note : this is a blocking call
