code: public void process() {
          processOverview();
          for ( ClassDoc doc : rootDoc.classes() ) {
              packages.add(doc.containingPackage());
              processClass(doc);
          }
          for ( PackageDoc doc : packages ) {
              processPackage(doc);
          }
      }
docs: Process the documentation tree. If any errors occur during processing,
  {@link #isError()} will return `true` afterwards.