Index: trunk/src/org/openstreetmap/josm/data/preferences/AbstractProperty.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/preferences/AbstractProperty.java	(revision 10938)
+++ trunk/src/org/openstreetmap/josm/data/preferences/AbstractProperty.java	(revision 10939)
@@ -14,5 +14,5 @@
 
     private final class PreferenceChangedListenerAdapter implements PreferenceChangedListener {
-        private ValueChangeListener<? super T> listener;
+        private final ValueChangeListener<? super T> listener;
 
         PreferenceChangedListenerAdapter(ValueChangeListener<? super T> listener) {
Index: trunk/src/org/openstreetmap/josm/data/preferences/AbstractToStringProperty.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/preferences/AbstractToStringProperty.java	(revision 10938)
+++ trunk/src/org/openstreetmap/josm/data/preferences/AbstractToStringProperty.java	(revision 10939)
@@ -25,5 +25,5 @@
      */
     public static class ChildProperty<T> extends AbstractToStringProperty<T> {
-        private AbstractToStringProperty<T> parent;
+        private final AbstractToStringProperty<T> parent;
 
         ChildProperty(AbstractToStringProperty<T> parent, String key) {
Index: trunk/src/org/openstreetmap/josm/gui/conflict/tags/TagConflictResolverModel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/conflict/tags/TagConflictResolverModel.java	(revision 10938)
+++ trunk/src/org/openstreetmap/josm/gui/conflict/tags/TagConflictResolverModel.java	(revision 10939)
@@ -22,5 +22,5 @@
     private transient TagCollection tags;
     private List<String> displayedKeys;
-    private Set<String> keysWithConflicts = new HashSet<>();
+    private final Set<String> keysWithConflicts = new HashSet<>();
     private transient Map<String, MultiValueResolutionDecision> decisions;
     private int numConflicts;
Index: trunk/src/org/openstreetmap/josm/gui/layer/imagery/TileCoordinateConverter.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/layer/imagery/TileCoordinateConverter.java	(revision 10938)
+++ trunk/src/org/openstreetmap/josm/gui/layer/imagery/TileCoordinateConverter.java	(revision 10939)
@@ -23,5 +23,5 @@
     private MapView mapView;
     private TileSourceDisplaySettings settings;
-    private TileSource tileSource;
+    private final TileSource tileSource;
 
     /**
Index: trunk/src/org/openstreetmap/josm/tools/ListenerList.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/ListenerList.java	(revision 10938)
+++ trunk/src/org/openstreetmap/josm/tools/ListenerList.java	(revision 10939)
@@ -35,5 +35,5 @@
     private static final class WeakListener<T> {
 
-        private WeakReference<T> listener;
+        private final WeakReference<T> listener;
 
         WeakListener(T listener) {
@@ -62,5 +62,5 @@
         @Override
         public String toString() {
-            return "WeakListener [listener=" + listener + "]";
+            return "WeakListener [listener=" + listener + ']';
         }
     }
@@ -165,6 +165,6 @@
      */
     public static class TracingListenerList<T> extends ListenerList<T> {
-        private HashMap<T, StackTraceElement[]> listenersAdded = new HashMap<>();
-        private HashMap<T, StackTraceElement[]> listenersRemoved = new HashMap<>();
+        private final HashMap<T, StackTraceElement[]> listenersAdded = new HashMap<>();
+        private final HashMap<T, StackTraceElement[]> listenersRemoved = new HashMap<>();
 
         protected TracingListenerList() {
Index: trunk/src/org/openstreetmap/josm/tools/bugreport/BugReportQueue.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/bugreport/BugReportQueue.java	(revision 10938)
+++ trunk/src/org/openstreetmap/josm/tools/bugreport/BugReportQueue.java	(revision 10939)
@@ -20,7 +20,7 @@
     private static final BugReportQueue INSTANCE = new BugReportQueue();
 
-    private LinkedList<ReportedException> reportsToDisplay = new LinkedList<>();
+    private final LinkedList<ReportedException> reportsToDisplay = new LinkedList<>();
     private boolean suppressAllMessages;
-    private ArrayList<ReportedException> suppressFor = new ArrayList<>();
+    private final ArrayList<ReportedException> suppressFor = new ArrayList<>();
     private Thread displayThread;
     private final BiFunction<ReportedException, Integer, SuppressionMode> bugReportHandler = getBestHandler();