code: protected void addPackageList(Content contentTree) throws IOException {
          Content caption = getTableCaption(configuration.getResource(
                  "doclet.ClassUse_Packages.that.use.0",
                  getLink(new LinkInfoImpl(configuration, LinkInfoImpl.Kind.CLASS_USE_HEADER, classdoc))));
          Content table = (configuration.isOutputHtml5())
                  ? HtmlTree.TABLE(HtmlStyle.useSummary, caption)
                  : HtmlTree.TABLE(HtmlStyle.useSummary, useTableSummary, caption);
          table.addContent(getSummaryTableHeader(packageTableHeader, "col"));
          Content tbody = new HtmlTree(HtmlTag.TBODY);
          Iterator<PackageDoc> it = pkgSet.iterator();
          for (int i = 0; it.hasNext(); i++) {
              PackageDoc pkg = it.next();
              HtmlTree tr = new HtmlTree(HtmlTag.TR);
              if (i % 2 == 0) {
                  tr.addStyle(HtmlStyle.altColor);
              } else {
                  tr.addStyle(HtmlStyle.rowColor);
              }
              addPackageUse(pkg, tr);
              tbody.addContent(tr);
          }
          table.addContent(tbody);
          Content li = HtmlTree.LI(HtmlStyle.blockList, table);
          contentTree.addContent(li);
      }
docs: Add the packages list that use the given class.
  
  @param contentTree the content tree to which the packages list will be added