code: public void delete() throws IOException {
          String idKey = idStrategy().keyFor(id);
          File existingUserFolder = getExistingUserFolder();
          UserIdMapper.getInstance().remove(id);
          AllUsers.remove(id);
          deleteExistingUserFolder(existingUserFolder);
          UserDetailsCache.get().invalidate(idKey);
      }
docs: Deletes the data directory and removes this user from Hudson.
  
  @throws IOException if we fail to delete.