Index: trunk/src/org/openstreetmap/josm/actions/CreateMultipolygonAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/CreateMultipolygonAction.java	(revision 8530)
+++ trunk/src/org/openstreetmap/josm/actions/CreateMultipolygonAction.java	(revision 8533)
@@ -332,5 +332,5 @@
     }
 
-    public static final List<String> DEFAULT_LINEAR_TAGS = Arrays.asList("barrier", "fence_type", "source");
+    private static final List<String> DEFAULT_LINEAR_TAGS = Arrays.asList("barrier", "fence_type", "source");
 
     /**
Index: trunk/src/org/openstreetmap/josm/data/osm/event/DatasetEventManager.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/event/DatasetEventManager.java	(revision 8530)
+++ trunk/src/org/openstreetmap/josm/data/osm/event/DatasetEventManager.java	(revision 8533)
@@ -33,6 +33,4 @@
         public void run() {
             while (!eventsInEDT.isEmpty()) {
-                List<AbstractDatasetChangedEvent> events = new ArrayList<>(eventsInEDT);
-
                 DataSet dataSet = null;
                 AbstractDatasetChangedEvent consolidatedEvent = null;
@@ -126,4 +124,8 @@
     }
 
+    /**
+     * Replies the unique instance.
+     * @return the unique instance
+     */
     public static DatasetEventManager getInstance() {
         return instance;
Index: trunk/src/org/openstreetmap/josm/data/projection/CustomProjection.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/projection/CustomProjection.java	(revision 8530)
+++ trunk/src/org/openstreetmap/josm/data/projection/CustomProjection.java	(revision 8533)
@@ -103,5 +103,5 @@
 
         /** Map of all parameters by key */
-        public static final Map<String, Param> paramsByKey = new HashMap<>();
+        static final Map<String, Param> paramsByKey = new HashMap<>();
         static {
             for (Param p : Param.values()) {
Index: trunk/src/org/openstreetmap/josm/data/projection/Projections.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/projection/Projections.java	(revision 8530)
+++ trunk/src/org/openstreetmap/josm/data/projection/Projections.java	(revision 8533)
@@ -7,8 +7,10 @@
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -36,4 +38,5 @@
 import org.openstreetmap.josm.io.CachedFile;
 import org.openstreetmap.josm.tools.Pair;
+import org.openstreetmap.josm.tools.Utils;
 
 /**
@@ -62,9 +65,9 @@
      * should be compatible to PROJ.4
      */
-    public static final Map<String, ProjFactory> projs = new HashMap<>();
-    public static final Map<String, Ellipsoid> ellipsoids = new HashMap<>();
-    public static final Map<String, Datum> datums = new HashMap<>();
-    public static final Map<String, NTV2GridShiftFileWrapper> nadgrids = new HashMap<>();
-    public static final Map<String, Pair<String, String>> inits = new HashMap<>();
+    static final Map<String, ProjFactory> projs = new HashMap<>();
+    static final Map<String, Ellipsoid> ellipsoids = new HashMap<>();
+    static final Map<String, Datum> datums = new HashMap<>();
+    static final Map<String, NTV2GridShiftFileWrapper> nadgrids = new HashMap<>();
+    static final Map<String, Pair<String, String>> inits = new HashMap<>();
 
     static {
@@ -216,3 +219,45 @@
         return Collections.unmodifiableCollection(allCodes);
     }
+
+    private static String listKeys(Map<String, ?> map) {
+        List<String> keys = new ArrayList<>(map.keySet());
+        Collections.sort(keys);
+        return Utils.join(", ", keys);
+    }
+
+    /**
+     * Replies the list of projections as string (comma separated).
+     * @return the list of projections as string (comma separated)
+     * @since 8533
+     */
+    public static String listProjs() {
+        return listKeys(projs);
+    }
+
+    /**
+     * Replies the list of ellipsoids as string (comma separated).
+     * @return the list of ellipsoids as string (comma separated)
+     * @since 8533
+     */
+    public static String listEllipsoids() {
+        return listKeys(ellipsoids);
+    }
+
+    /**
+     * Replies the list of datums as string (comma separated).
+     * @return the list of datums as string (comma separated)
+     * @since 8533
+     */
+    public static String listDatums() {
+        return listKeys(datums);
+    }
+
+    /**
+     * Replies the list of nadgrids as string (comma separated).
+     * @return the list of nadgrids as string (comma separated)
+     * @since 8533
+     */
+    public static String listNadgrids() {
+        return listKeys(nadgrids);
+    }
 }
Index: trunk/src/org/openstreetmap/josm/gui/preferences/projection/CustomProjectionChoice.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/preferences/projection/CustomProjectionChoice.java	(revision 8530)
+++ trunk/src/org/openstreetmap/josm/gui/preferences/projection/CustomProjectionChoice.java	(revision 8533)
@@ -9,5 +9,4 @@
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -15,5 +14,4 @@
 import java.util.LinkedList;
 import java.util.List;
-import java.util.Map;
 
 import javax.swing.JButton;
@@ -36,5 +34,4 @@
 import org.openstreetmap.josm.tools.GBC;
 import org.openstreetmap.josm.tools.ImageProvider;
-import org.openstreetmap.josm.tools.Utils;
 
 public class CustomProjectionChoice extends AbstractProjectionChoice implements SubPrefsOptions {
@@ -171,5 +168,5 @@
             s.append("<b>+proj=...</b> - <i>").append(tr("Projection name"))
              .append("</i><br>&nbsp;&nbsp;&nbsp;&nbsp;").append(tr("Supported values:")).append(' ')
-             .append(listKeys(Projections.projs))
+             .append(Projections.listProjs())
              .append("<br><b>+lat_0=..., +lat_1=..., +lat_2=...</b> - <i>").append(tr("Projection parameters"))
              .append("</i><br><b>+x_0=..., +y_0=...</b> - <i>").append(tr("False easting and false northing"))
@@ -178,13 +175,13 @@
              .append("</i><br><b>+ellps=...</b> - <i>").append(tr("Ellipsoid name"))
              .append("</i><br>&nbsp;&nbsp;&nbsp;&nbsp;").append(tr("Supported values:")).append(' ')
-             .append(listKeys(Projections.ellipsoids))
+             .append(Projections.listEllipsoids())
              .append("<br><b>+a=..., +b=..., +rf=..., +f=..., +es=...</b> - <i>").append(tr("Ellipsoid parameters"))
              .append("</i><br><b>+datum=...</b> - <i>").append(tr("Datum name"))
              .append("</i><br>&nbsp;&nbsp;&nbsp;&nbsp;").append(tr("Supported values:")).append(' ')
-             .append(listKeys(Projections.datums))
+             .append(Projections.listDatums())
              .append("<br><b>+towgs84=...</b> - <i>").append(tr("3 or 7 term datum transform parameters"))
              .append("</i><br><b>+nadgrids=...</b> - <i>").append(tr("NTv2 grid file"))
              .append("</i><br>&nbsp;&nbsp;&nbsp;&nbsp;").append(tr("Built-in:")).append(' ')
-             .append(listKeys(Projections.nadgrids))
+             .append(Projections.listNadgrids())
              .append("<br><b>+bounds=</b>minlon,minlat,maxlon,maxlat - <i>").append(tr("Projection bounds (in degrees)"))
              .append("</i><br><b>+wmssrs=</b>EPSG:123456 - <i>").append(tr("Sets the SRS=... parameter in the WMS request"))
@@ -192,10 +189,4 @@
 
             return new HtmlPanel(s.toString());
-        }
-
-        private String listKeys(Map<String, ?> map) {
-            List<String> keys = new ArrayList<>(map.keySet());
-            Collections.sort(keys);
-            return Utils.join(", ", keys);
         }
     }