diff --git a/src/main/java/org/codelibs/fess/app/web/admin/scheduler/AdminSchedulerAction.java b/src/main/java/org/codelibs/fess/app/web/admin/scheduler/AdminSchedulerAction.java
index 43c09f4b4..2b832858e 100644
--- a/src/main/java/org/codelibs/fess/app/web/admin/scheduler/AdminSchedulerAction.java
+++ b/src/main/java/org/codelibs/fess/app/web/admin/scheduler/AdminSchedulerAction.java
@@ -183,7 +183,7 @@ public class AdminSchedulerAction extends FessAdminAction {
         verifyCrudMode(crudMode, CrudMode.DETAILS);
         saveToken();
         return asHtml(path_AdminScheduler_AdminSchedulerDetailsJsp).renderWith(data -> {
-            data.register("systemJobId", fessConfig.isSystemJobId(id));
+            RenderDataUtil.register(data, "systemJobId", fessConfig.isSystemJobId(id));
         }).useForm(EditForm.class, op -> {
             op.setup(form -> {
                 scheduledJobService.getScheduledJob(id).ifPresent(entity -> {
@@ -369,7 +369,7 @@ public class AdminSchedulerAction extends FessAdminAction {
 
     private HtmlResponse asDetailsHtml(String id) {
         return asHtml(path_AdminScheduler_AdminSchedulerDetailsJsp).renderWith(data -> {
-            data.register("systemJobId", fessConfig.isSystemJobId(id));
+            RenderDataUtil.register(data, "systemJobId", fessConfig.isSystemJobId(id));
         });
     }
 }
diff --git a/src/main/java/org/codelibs/fess/util/RenderDataUtil.java b/src/main/java/org/codelibs/fess/util/RenderDataUtil.java
index b35711219..73c0fac9c 100644
--- a/src/main/java/org/codelibs/fess/util/RenderDataUtil.java
+++ b/src/main/java/org/codelibs/fess/util/RenderDataUtil.java
@@ -26,7 +26,9 @@ import org.lastaflute.web.response.render.RenderData;
 public class RenderDataUtil {
 
     public static void register(final RenderData data, final String key, final Object value) {
-        if (value instanceof Entity) {
+        if (value == null) {
+            return;
+        } else if (value instanceof Entity) {
             data.register(key, BeanUtil.copyBeanToNewMap(value));
         } else if (value instanceof Collection<?>) {
             final Collection<?> coll = ((Collection<?>) value);