code: private void buildTree(ClassDoc[] classes, Configuration configuration) {
          for (int i = 0; i < classes.length; i++) {
              // In the tree page (e.g overview-tree.html) do not include
              // information of classes which are deprecated or are a part of a
              // deprecated package.
              if (configuration.nodeprecated &&
                      (Util.isDeprecated(classes[i]) ||
                      Util.isDeprecated(classes[i].containingPackage()))) {
                  continue;
              }
  
              if (configuration.javafx
                      && classes[i].tags("treatAsPrivate").length > 0) {
                  continue;
              }
  
              if (classes[i].isEnum()) {
                  processType(classes[i], configuration, baseEnums, subEnums);
              } else if (classes[i].isClass()) {
                  processType(classes[i], configuration, baseclasses, subclasses);
              } else if (classes[i].isInterface()) {
                  processInterface(classes[i]);
                  List<ClassDoc> list = implementingclasses.get(classes[i]);
                  if (list != null) {
                      Collections.sort(list);
                  }
              } else if (classes[i].isAnnotationType()) {
                  processType(classes[i], configuration, baseAnnotationTypes,
                      subAnnotationTypes);
              }
          }
  
          Collections.sort(baseinterfaces);
          for (Iterator<List<ClassDoc>> it = subinterfaces.values().iterator(); it.hasNext(); ) {
              Collections.sort(it.next());
          }
          for (Iterator<List<ClassDoc>> it = subclasses.values().iterator(); it.hasNext(); ) {
              Collections.sort(it.next());
          }
      }
docs: Generate mapping for the sub-classes for every class in this run.
  Return the sub-class list for java.lang.Object which will be having
  sub-class listing for itself and also for each sub-class itself will
  have their own sub-class lists.
  
  @param classes all the classes in this run.
  @param configuration the current configuration of the doclet.