diff --git a/source/client/src/clientTmqConnector.c b/source/client/src/clientTmqConnector.c
index 6b0bfc09e897e381f141673602efa4d7d25f3a93..08c802d967ae00ed94d1a99fa69d44a4a0367cc9 100644
--- a/source/client/src/clientTmqConnector.c
+++ b/source/client/src/clientTmqConnector.c
@@ -394,7 +394,7 @@ JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_tmq_TMQConnector_tmqGetOffset(JNI
   TAOS_RES *res = (TAOS_RES *)jres;
   if (res == NULL) {
     jniDebug("jobj:%p, invalid res handle", jobj);
-    return NULL;
+    return -1;
   }
   return tmq_get_vgroup_offset(res);
 }