Properly handle null in critical notifications (#16592)

Change-Id: I85994e47f99e2ac5431e67c56f432380e84af23d

2 files changed, 26 insertions, 2 deletions

diff --git a/server/src/com/vaadin/server/VaadinService.java b/server/src/com/vaadin/server/VaadinService.java
index 36d6910a7a..2aaab31dd1 100644
--- a/server/src/com/vaadin/server/VaadinService.java
+++ b/server/src/com/vaadin/server/VaadinService.java
@@ -1581,8 +1581,18 @@ public abstract class VaadinService implements Serializable {
             }
 
             JsonObject appError = Json.createObject();
-            appError.put("caption", caption);
-            appError.put("message", message);
+            if (caption == null) {
+                appError.put("caption", Json.createNull());
+            } else {
+                appError.put("caption", caption);
+            }
+
+            if (message == null) {
+                appError.put("message", Json.createNull());
+            } else {
+                appError.put("message", message);
+            }
+
             if (url == null) {
                 appError.put("url", Json.createNull());
             } else {
diff --git a/server/tests/src/com/vaadin/server/VaadinServiceTest.java b/server/tests/src/com/vaadin/server/VaadinServiceTest.java
index 51325067d2..c2ca8b0e57 100644
--- a/server/tests/src/com/vaadin/server/VaadinServiceTest.java
+++ b/server/tests/src/com/vaadin/server/VaadinServiceTest.java
@@ -66,4 +66,18 @@ public class VaadinServiceTest {
         Assert.assertEquals("SessionDestroyListeners not called exactly once",
                 1, listener.callCount);
     }
+
+    @Test
+    public void testCriticalNotificationNullHandling() {
+        for (String caption : new String[] { "some caption", null }) {
+            for (String message : new String[] { "some message", null }) {
+                for (String details : new String[] { "some details", null }) {
+                    for (String url : new String[] { "some url", null }) {
+                        VaadinService.createCriticalNotificationJSON(caption,
+                                message, details, url);
+                    }
+                }
+            }
+        }
+    }
 }