Index: applications/viewer/jmapviewer/src/org/openstreetmap/gui/jmapviewer/tilesources/AbstractTMSTileSource.java
===================================================================
--- applications/viewer/jmapviewer/src/org/openstreetmap/gui/jmapviewer/tilesources/AbstractTMSTileSource.java	(revision 32085)
+++ applications/viewer/jmapviewer/src/org/openstreetmap/gui/jmapviewer/tilesources/AbstractTMSTileSource.java	(revision 32113)
@@ -186,5 +186,5 @@
             }
         }
-        if (noTileChecksums != null) {
+        if (noTileChecksums != null && content != null) {
             for (Entry<String, Set<String>> searchEntry: noTileChecksums.entrySet()) {
                 MessageDigest md = null;