code: private void obtainClassInfoRecursive(final Set<ClassInfo> reachableClassInfo) {
          reachableClassInfo.addAll(memberClassNameToClassInfo.values());
          for (final PackageInfo subPackageInfo : getChildren()) {
              subPackageInfo.obtainClassInfoRecursive(reachableClassInfo);
          }
      }
docs: Get the {@link ClassInfo} objects within this package recursively.
  
  @param reachableClassInfo
  the reachable class info