public static <T>String join(List<T> list,String separator,T nullReplacement){
  if (list == null) {
    return null;
  }
  List<T> objects=new ArrayList<>(list);
  if (nullReplacement != null) {
    Collections.replaceAll(objects,null,nullReplacement);
  }
  return StringUtils.join(objects,separator);
}

public static < T > String join ( List < T > list , String separator , T nullReplacement ) { if ( list == null ) { return null ; } List < T > objects = new ArrayList < > ( list ) ; if ( nullReplacement != null ) { Collections . replaceAll ( objects , null , nullReplacement ) ; } return StringUtils . join ( objects , separator ) ; }
joins the elements of the provided array into a single string containing the provided list of elements .
