code: public Set<? extends Element> getSpecifiedElements() {
          if (specifiedElements == null) {
              Set<Element> result = new LinkedHashSet<>();
              result.addAll(specifiedModuleElements);
              result.addAll(specifiedPackageElements);
              result.addAll(specifiedTypeElements);
              specifiedElements = Collections.unmodifiableSet(result);
          }
          return specifiedElements;
      }
docs: Returns a set of elements specified on the
  command line, including any inner classes.
  
  @return the set of elements specified on the command line