private List<File> combine(List<File> listA,List<File> listB){
  LinkedHashSet<File> combinedProjects=Sets.newLinkedHashSet(listA);
  combinedProjects.addAll(listB);
  return new ArrayList<>(combinedProjects);
}

private List < File > combine ( List < File > listA , List < File > listB ) { LinkedHashSet < File > combinedProjects = Sets . newLinkedHashSet ( listA ) ; combinedProjects . addAll ( listB ) ; return new ArrayList < > ( combinedProjects ) ; }
combine lista and listb to a single list without duplicates .
