code: private void resetPackageList() {
  		final Set<PackageDoc> set = new TreeSet<>();
          for (final PackageDoc pack : this.root.specifiedPackages()) {
              set.add(pack);
          }
          for (final ClassDoc clazz : this.root.specifiedClasses()) {
              set.add(clazz.containingPackage());
          }
          this.packages = Utils.toArray(this.packages, set);
  	}
docs: Reset the list of packages for avoiding duplicates.
  
  <p>The inherited implementation uses a HashSet that allow
  the same package to be stored multiple times. Here,
  we uses a TreeSet for using the "compareTo" mechanism.