code: public String convertFieldSetToString(Set<String> fieldSet) {
  
  		if (fieldSet == null || fieldSet.isEmpty() || fieldSet.contains("*")) {
  			return "*";
  		}
  
  		Set<String> interim = fieldSet.stream().filter(s -> !StringUtils.isBlank(s)).collect(Collectors.toSet());
  		if (interim.isEmpty()) {
  			interim.add(ID);
  		}
  		return interim.stream().collect(Collectors.joining(","));
  
  	}
docs: Converts the Set to a string. Adds the id field if only blank fields present. If fieldset is null returns "*"
  
  @param fieldSet
  @return