code: public void syncUsers(boolean createUsers, boolean deleteUsers) {
  		List<String> realmUserNames = externalUsersService.getUserNames();
  		if (LOG.isDebugEnabled()) {
  			LOG.debug("Synchronize for realm=" + realm + " users=" + realmUserNames.size() + " (createUsers = " + createUsers + ", deleteUsers = " + deleteUsers + ")");
  		}
  		
  		for (String username : realmUserNames) {
  			User user = externalUsersService.getUser(username);
  			applyPatch(user);
  			if (createUsers) {
  				createOrUpdateUser(user);
  			} else if (userExists(user.getUsername())) {
  				updateUser(user);
  			}
  			
  			List<String> groupNames = externalUsersService.getGroupNames(username);
  			updateUserGroups(username, groupNames);
  		}
  		
  		if (deleteUsers) {
  			deleteAsyncUsers(realmUserNames);
  		}
  	}
docs: from NextServerSession doesn't work