juick-xmpp: fix reconnection

1 files changed, 1 insertions, 1 deletions

diff --git a/juick-core/src/main/java/com/juick/xml/adapters/SimpleDateAdapter.java b/juick-core/src/main/java/com/juick/xml/adapters/SimpleDateAdapter.java
index 264f8c22..1093e47a 100644
--- a/juick-core/src/main/java/com/juick/xml/adapters/SimpleDateAdapter.java
+++ b/juick-core/src/main/java/com/juick/xml/adapters/SimpleDateAdapter.java
@@ -21,7 +21,7 @@ public class SimpleDateAdapter extends XmlAdapter<String, Date> {
     @Override
     public String marshal(Date v) throws Exception {
         if (v == null) {
-            return "";
+            return null;
         }
         synchronized (dateFormat) {
             return dateFormat.format(v);