fix ISE when synchronizing claims

Author: Blue-B-code

claimManagement/src/main/java/org/openimis/imisclaims/usecase/CheckMutation.java

@@ -40,22 +40,29 @@ public CheckMutation(long timeOutMs, long delayMs, @NonNull CheckMutationGraphQL
     public Integer execute(@NonNull String uuid, @NonNull String message) throws Exception {
         long start = System.currentTimeMillis();
         CheckMutationQuery.Node node = null;
-        Integer status;
+        Integer status = null;
         do {
+            if (System.currentTimeMillis() >= start + timeOutMs) {
+                throw new TimeoutException("Could not retrieve the mutation status of '" + uuid + "' within " + timeOutMs + "ms");
+            }
             if (node != null) {
                 Thread.sleep(delayMs);
             }
-            node = request.execute(uuid);
-            status = node.status();
-            if (System.currentTimeMillis() >= start + timeOutMs) {
-                throw new TimeoutException("Could not retrieve the mutation status of '" + uuid + "' within " + timeOutMs + "ms");
+            try {
+                node = request.execute(uuid);
+                if (node != null) {
+                    status = node.status();
+                } else {
+                    status = STATUS_RECEIVED;
+                }
+            } catch (Exception e) {
+                status = STATUS_RECEIVED;
             }
         } while (status == null || status == STATUS_RECEIVED);
-
         if (status == STATUS_ERROR) {
-            throw new IllegalStateException(message + ":\n" + getErrorDetail(node.error()));
+            String errorMsg = (node != null) ? getErrorDetail(node.error()) : "Unknown server error";
+            throw new IllegalStateException(message + ":\n" + errorMsg);
         }
-
         return status;
     }