Fixed warnings, simplification

app/src/main/java/eu/faircode/email/Core.java

@@ -561,7 +561,6 @@ class Core {
             }
 
             ifolder.expunge();
-
         } else {
             // Mark source read
             if (autoread)
@@ -1241,7 +1240,6 @@ class Core {
             IMAPFolder ifolder, IMAPMessage imessage,
             boolean browsed,
             List<EntityRule> rules) throws MessagingException, IOException {
-        synchronized (folder) {
         long uid = ifolder.getUID(imessage);
 
         if (imessage.isExpunged()) {
@@ -1508,7 +1506,6 @@ class Core {
 
         return message;
     }
-    }
 
     private static EntityIdentity matchIdentity(Context context, EntityFolder folder, EntityMessage message) {
         DB db = DB.getInstance(context);
@@ -1743,6 +1740,8 @@ class Core {
         Log.i("Notify messages=" + messages.size());
 
         NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+        if (nm == null)
+            return;
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
         boolean badge = prefs.getBoolean("badge", true);
@@ -1844,7 +1843,8 @@ class Core {
         List<Notification> notifications = new ArrayList<>();
         // https://developer.android.com/training/notify-user/group
 
-        if (messages == null || messages.size() == 0)
+        NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+        if (messages == null || messages.size() == 0 || nm == null)
             return notifications;
 
         boolean pro = Helper.isPro(context);
@@ -1860,8 +1860,6 @@ class Core {
         boolean notify_flag = prefs.getBoolean("notify_flag", false) && pro;
         boolean notify_seen = prefs.getBoolean("notify_seen", true);
 
-        NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
-
         // Get contact info
         Map<TupleMessageEx, ContactInfo> messageContact = new HashMap<>();
         for (TupleMessageEx message : messages)
@@ -2138,12 +2136,14 @@ class Core {
 
         EntityLog.log(context, title + " " + Helper.formatThrowable(ex));
 
+        NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+        if (nm == null)
+            return;
+
         if (ex instanceof AuthenticationFailedException || // Also: Too many simultaneous connections
                 ex instanceof AlertException ||
-                ex instanceof SendFailedException) {
+                ex instanceof SendFailedException)
-            NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
             nm.notify(tag, 1, getNotificationError(context, title, ex).build());
-        }
 
         // connection failure: Too many simultaneous connections
 
@@ -2160,11 +2160,9 @@ class Core {
                 !(ex instanceof MessagingException && ex.getCause() instanceof SocketException) &&
                 !(ex instanceof MessagingException && ex.getCause() instanceof SocketTimeoutException) &&
                 !(ex instanceof MessagingException && ex.getCause() instanceof SSLException) &&
-                !(ex instanceof MessagingException && "connection failure".equals(ex.getMessage()))) {
+                !(ex instanceof MessagingException && "connection failure".equals(ex.getMessage())))
-            NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
             nm.notify(tag, 1, getNotificationError(context, title, ex).build());
     }
-    }
 
     static NotificationCompat.Builder getNotificationError(Context context, String title, Throwable ex) {
         return getNotificationError(context, "error", title, ex, true);