private Collection<URI> removeDuplicateURIs(Collection<URI> uris){
  HashSet<URI> set=new HashSet<URI>();
  set.addAll(uris);
  return set;
}

private Collection < URI > removeDuplicateURIs ( Collection < URI > uris ) { HashSet < URI > set = new HashSet < URI > ( ) ; set . addAll ( uris ) ; return set ; }
removes duplicate uris from a collection .
