code: public void addSubInterfacesInfo(Content classInfoTree) {
          if (classDoc.isInterface()) {
              List<ClassDoc> subInterfaces = classtree.allSubs(classDoc, false);
              if (subInterfaces.size() > 0) {
                  Content label = getResource(
                          "doclet.Subinterfaces");
                  Content dt = HtmlTree.DT(label);
                  Content dl = HtmlTree.DL(dt);
                  dl.addContent(getClassLinks(LinkInfoImpl.Kind.SUBINTERFACES,
                          subInterfaces));
                  classInfoTree.addContent(dl);
              }
          }
      }
docs: {@inheritDoc}