Fix Null pointer exception

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/admin/GroupManagementAdminServiceImpl.java

@@ -40,8 +40,12 @@ public class GroupManagementAdminServiceImpl implements GroupManagementAdminServ
         try {
             RequestValidationUtil.validatePaginationParameters(offset, limit);
             GroupPaginationRequest request = new GroupPaginationRequest(offset, limit);
+            if (name != null){
                 request.setGroupName(name.toUpperCase());
+            }
+            if (owner != null) {
                 request.setOwner(owner.toUpperCase());
+            }
             PaginationResult deviceGroupsResult = DeviceMgtAPIUtils.getGroupManagementProviderService()
                     .getGroups(request);
             DeviceGroupList deviceGroupList = new DeviceGroupList();