synchronize around adding query to query map

1 files changed, 3 insertions, 1 deletions

diff --git a/src/main/java/de/pixart/messenger/services/MessageArchiveService.java b/src/main/java/de/pixart/messenger/services/MessageArchiveService.java
index c74a71b08..5a5b0e9a1 100644
--- a/src/main/java/de/pixart/messenger/services/MessageArchiveService.java
+++ b/src/main/java/de/pixart/messenger/services/MessageArchiveService.java
@@ -75,7 +75,9 @@ public class MessageArchiveService implements OnAdvancedStreamFeaturesLoaded {
             query = new Query(account, startCatchup, endCatchup);
             query.reference = reference;
         }
-        this.queries.add(query);
+        synchronized (this.queries) {
+            this.queries.add(query);
+        }
         this.execute(query);
     }