Index: trunk/src/org/openstreetmap/josm/data/Preferences.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 6598)
+++ trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 6599)
@@ -1026,5 +1026,6 @@
         CheckParameterUtil.ensureParameterNotNull(key);
         CheckParameterUtil.ensureParameterNotNull(def);
-        if (defaultsMap.containsKey(key) && !def.equals(defaultsMap.get(key))) {
+        Setting oldDef = defaultsMap.get(key);
+        if (oldDef != null && oldDef.getValue() != null && def.getValue() != null && !def.equals(oldDef)) {
             Main.info("Defaults for " + key + " differ: " + def + " != " + defaultsMap.get(key));
         }
Index: trunk/src/org/openstreetmap/josm/data/oauth/OAuthParameters.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/oauth/OAuthParameters.java	(revision 6598)
+++ trunk/src/org/openstreetmap/josm/data/oauth/OAuthParameters.java	(revision 6599)
@@ -91,5 +91,5 @@
      */
     static public OAuthParameters createFromPreferences(Preferences pref) {
-        OAuthParameters parameters = createDefault(pref.get("osm-server.url", OsmApi.DEFAULT_API_URL));
+        OAuthParameters parameters = createDefault(pref.get("osm-server.url"));
         parameters.setConsumerKey(pref.get("oauth.settings.consumer-key", parameters.getConsumerKey()));
         parameters.setConsumerSecret(pref.get("oauth.settings.consumer-secret", parameters.getConsumerSecret()));
Index: trunk/src/org/openstreetmap/josm/gui/oauth/OsmOAuthAuthorizationClient.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/oauth/OsmOAuthAuthorizationClient.java	(revision 6598)
+++ trunk/src/org/openstreetmap/josm/gui/oauth/OsmOAuthAuthorizationClient.java	(revision 6599)
@@ -35,5 +35,4 @@
 import org.openstreetmap.josm.gui.progress.NullProgressMonitor;
 import org.openstreetmap.josm.gui.progress.ProgressMonitor;
-import org.openstreetmap.josm.io.OsmApi;
 import org.openstreetmap.josm.io.OsmTransferCanceledException;
 import org.openstreetmap.josm.tools.CheckParameterUtil;
@@ -62,5 +61,5 @@
      */
     public OsmOAuthAuthorizationClient() {
-        oauthProviderParameters = OAuthParameters.createDefault(Main.pref.get("osm-server.url", OsmApi.DEFAULT_API_URL));
+        oauthProviderParameters = OAuthParameters.createDefault(Main.pref.get("osm-server.url"));
         consumer = oauthProviderParameters.buildConsumer();
         provider = oauthProviderParameters.buildProvider(consumer);