code: @SuppressWarnings("deprecation")
      private boolean hasOldTaglet(List<String> tagletNames, List<File> tagletPaths) throws ToolException {
          if (!fileManager.hasLocation(TAGLET_PATH)) {
              try {
                  ((StandardJavaFileManager) fileManager).setLocation(TAGLET_PATH, tagletPaths);
              } catch (IOException ioe) {
                  String text = messager.getText("main.doclet_could_not_set_location", tagletPaths);
                  throw new ToolException(CMDERR, text, ioe);
              }
          }
          ClassLoader cl = fileManager.getClassLoader(TAGLET_PATH);
          if (cl == null) {
              // no classloader found!
              String text = messager.getText("main.doclet_no_classloader_found", tagletNames.get(0));
              throw new ToolException(CMDERR, text);
          }
          for (String tagletName : tagletNames) {
              try {
                  Class<?> klass = cl.loadClass(tagletName);
                  if (com.sun.tools.doclets.Taglet.class.isAssignableFrom(klass)) {
                      return true;
                  }
              } catch (ClassNotFoundException cnfe) {
                  String text = messager.getText("main.doclet_class_not_found", tagletName);
                  throw new ToolException(CMDERR, text, cnfe);
              }
          }
          return false;
      }
docs: /*
  This method returns true iff it finds a legacy taglet, but for
  all other conditions including errors it returns false, allowing
  nature to take its own course.