code: private Set<String> getParameterAsSet(String name) {
          String[] values = getParameterValues(name);
          if (values == null) {
              return null;
          }
  
          Set<String> valueSet = new LinkedHashSet<>(values.length);
          Collections.addAll(valueSet, values);
          return valueSet;
      }
docs: Returns the value of an activity's request parameter as a {@code Set},
  or {@code null} if the parameter does not exist.
  
  @param name a {@code String} specifying the name of the parameter
  @return a {@code Set} objects containing the parameter's values