Fixed NPE in UI check (#11714)

Change-Id: I837a15c2ac58119ec203c1b214e19381184c8617

diff --git a/server/src/com/vaadin/server/communication/ServerRpcHandler.java b/server/src/com/vaadin/server/communication/ServerRpcHandler.java
index e0e7494ca8e54c27a78c3bea0e8d9d3894d00081..3cc85909ee8cbb21f934fdb92c550c016811f0f6 100644 (file)
--- a/server/src/com/vaadin/server/communication/ServerRpcHandler.java
+++ b/server/src/com/vaadin/server/communication/ServerRpcHandler.java
@@ -193,7 +193,8 @@ public class ServerRpcHandler implements Serializable {
                     getLogger().warning(msg);
                     continue;
                 }
-                if (connector.getUI().isClosing()) {
+                // DragAndDropService has null UI
+                if (connector.getUI() != null && connector.getUI().isClosing()) {
                     String msg = "Ignoring RPC call for connector "
                             + connector.getClass().getName();
                     if (connector instanceof Component) {