private static int nonEmptyLists(List<?>... lists){
  int nonEmpty=0;
  for (  List<?> list : lists) {
    if (list != null && list.size() > 0) {
      ++nonEmpty;
    }
  }
  return nonEmpty;
}

private static int nonEmptyLists ( List < ? > ... lists ) { int nonEmpty = 0 ; for ( List < ? > list : lists ) { if ( list != null && list . size ( ) > 0 ) { ++ nonEmpty ; } } return nonEmpty ; }
returns the number of empty lists among the argument lists .
