Index: lams_admin/src/java/org/lamsfoundation/lams/admin/web/controller/UserOrgSaveController.java
===================================================================
diff -u -r064661349150076f41ef249b55b054a72f6a3fb5 -r7c51ceda8c7083514fd270dfc867689565bf1084
--- lams_admin/src/java/org/lamsfoundation/lams/admin/web/controller/UserOrgSaveController.java	(.../UserOrgSaveController.java)	(revision 064661349150076f41ef249b55b054a72f6a3fb5)
+++ lams_admin/src/java/org/lamsfoundation/lams/admin/web/controller/UserOrgSaveController.java	(.../UserOrgSaveController.java)	(revision 7c51ceda8c7083514fd270dfc867689565bf1084)
@@ -113,7 +113,8 @@
 	Organisation organisation = (Organisation) userManagementService.findById(Organisation.class, orgId);
 	Set uos = organisation.getUserOrganisations();
 
-	String[] userIds = StringUtils.isBlank(userOrgForm.getUserIds()) ? null : userOrgForm.getUserIds().split(",");
+	String[] userIds = StringUtils.isBlank(userOrgForm.getUserIds()) ? new String[0]
+		: userOrgForm.getUserIds().split(",");
 	List<Integer> userIdList = Arrays.stream(userIds).filter(StringUtils::isNotBlank)
 		.collect(Collectors.mapping(userId -> Integer.valueOf(userId), Collectors.toList()));
 	log.debug("new user membership of orgId=" + orgId + " will be: " + userIdList);