Index: /trunk/src/org/openstreetmap/josm/command/DeleteCommand.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/command/DeleteCommand.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/command/DeleteCommand.java	(revision 12869)
@@ -103,5 +103,5 @@
     }
 
-    private static DeletionCallback callback;
+    private static volatile DeletionCallback callback;
 
     /**
Index: /trunk/src/org/openstreetmap/josm/command/SplitWayCommand.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/command/SplitWayCommand.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/command/SplitWayCommand.java	(revision 12869)
@@ -38,5 +38,5 @@
 public class SplitWayCommand extends SequenceCommand {
 
-    private static Consumer<String> warningNotifier = msg -> Logging.warn(msg);
+    private static volatile Consumer<String> warningNotifier = msg -> Logging.warn(msg);
 
     /**
Index: /trunk/src/org/openstreetmap/josm/data/PreferencesUtils.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/PreferencesUtils.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/data/PreferencesUtils.java	(revision 12869)
@@ -33,5 +33,5 @@
 public final class PreferencesUtils {
 
-    private static StringBuilder summary = new StringBuilder();
+    private static volatile StringBuilder summary = new StringBuilder();
 
     private PreferencesUtils() {
Index: /trunk/src/org/openstreetmap/josm/gui/MainApplication.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/MainApplication.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/gui/MainApplication.java	(revision 12869)
@@ -178,5 +178,5 @@
      * Command-line arguments used to run the application.
      */
-    private static List<String> commandLineArgs;
+    private static volatile List<String> commandLineArgs;
 
     /**
@@ -226,5 +226,5 @@
      * @since 12641
      */
-    public static UndoRedoHandler undoRedo;
+    public static volatile UndoRedoHandler undoRedo;
 
     private static final LayerChangeListener undoRedoCleaner = new LayerChangeListener() {
Index: /trunk/src/org/openstreetmap/josm/io/MessageNotifier.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/MessageNotifier.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/io/MessageNotifier.java	(revision 12869)
@@ -47,5 +47,5 @@
     }
 
-    private static NotifierCallback callback;
+    private static volatile NotifierCallback callback;
 
     /**
Index: /trunk/src/org/openstreetmap/josm/io/OsmConnection.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/OsmConnection.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/io/OsmConnection.java	(revision 12869)
@@ -50,5 +50,5 @@
     }
 
-    static OAuthAccessTokenFetcher fetcher = u -> {
+    static volatile OAuthAccessTokenFetcher fetcher = u -> {
         throw new JosmRuntimeException("OsmConnection.setOAuthAccessTokenFetcher() has not been called");
     };
Index: /trunk/src/org/openstreetmap/josm/io/auth/AbstractCredentialsAgent.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/auth/AbstractCredentialsAgent.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/io/auth/AbstractCredentialsAgent.java	(revision 12869)
@@ -37,5 +37,6 @@
     }
 
-    private static CredentialsProvider credentialsProvider = (a, b, c, d, e, f) -> Logging.error("Credentials provider has not been set");
+    private static volatile CredentialsProvider credentialsProvider =
+            (a, b, c, d, e, f) -> Logging.error("Credentials provider has not been set");
 
     /**
Index: /trunk/src/org/openstreetmap/josm/tools/OsmUrlToBounds.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/OsmUrlToBounds.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/tools/OsmUrlToBounds.java	(revision 12869)
@@ -24,5 +24,5 @@
     private static final String SHORTLINK_PREFIX = "http://osm.org/go/";
 
-    private static Supplier<Dimension> mapSize = () -> new Dimension(800, 600);
+    private static volatile Supplier<Dimension> mapSize = () -> new Dimension(800, 600);
 
     private OsmUrlToBounds() {
Index: /trunk/src/org/openstreetmap/josm/tools/bugreport/BugReportSender.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/bugreport/BugReportSender.java	(revision 12868)
+++ /trunk/src/org/openstreetmap/josm/tools/bugreport/BugReportSender.java	(revision 12869)
@@ -72,5 +72,5 @@
     };
 
-    private static BugReportSendingHandler handler = FALLBACK_BUGREPORT_SENDING_HANDLER;
+    private static volatile BugReportSendingHandler handler = FALLBACK_BUGREPORT_SENDING_HANDLER;
 
     private final String statusText;