Index: /trunk/src/org/openstreetmap/josm/data/Preferences.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 11435)
+++ /trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 11436)
@@ -32,4 +32,5 @@
 import java.util.MissingResourceException;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.ResourceBundle;
 import java.util.Set;
@@ -68,4 +69,5 @@
 import org.openstreetmap.josm.data.preferences.Setting;
 import org.openstreetmap.josm.data.preferences.StringSetting;
+import org.openstreetmap.josm.gui.preferences.SourceEditor.ExtendedSourceEntry;
 import org.openstreetmap.josm.gui.preferences.validator.ValidatorTagCheckerRulesPreference;
 import org.openstreetmap.josm.gui.preferences.validator.ValidatorTagCheckerRulesPreference.RulePrefHelper;
@@ -1584,5 +1586,8 @@
             if (l.stream().noneMatch(x -> x.values().contains(url))) {
                 RulePrefHelper helper = ValidatorTagCheckerRulesPreference.RulePrefHelper.INSTANCE;
-                l.add(helper.serialize(helper.getDefault().stream().filter(x -> url.equals(x.url)).findFirst().get()));
+                Optional<ExtendedSourceEntry> val = helper.getDefault().stream().filter(x -> url.equals(x.url)).findFirst();
+                if (val.isPresent()) {
+                    l.add(helper.serialize(val.get()));
+                }
                 putListOfStructs(key, l);
             }
Index: /trunk/src/org/openstreetmap/josm/gui/layer/gpx/GpxDrawHelper.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/layer/gpx/GpxDrawHelper.java	(revision 11435)
+++ /trunk/src/org/openstreetmap/josm/gui/layer/gpx/GpxDrawHelper.java	(revision 11436)
@@ -144,6 +144,6 @@
 
     // copied value for line drawing
-    private List<Integer> heatMapPolyX = new ArrayList<>();
-    private List<Integer> heatMapPolyY = new ArrayList<>();
+    private final List<Integer> heatMapPolyX = new ArrayList<>();
+    private final List<Integer> heatMapPolyY = new ArrayList<>();
 
     // setup color maps used by heat map
@@ -369,5 +369,5 @@
                          "(" +
                          "segments= " + visibleSegments.size() +
-                         ", per 10000 = " + Utils.getDurationString(10000 * timeDiff / visibleSegments.size()) +
+                         ", per 10000 = " + Utils.getDurationString(10_000 * timeDiff / visibleSegments.size()) +
                          ")"
               );
@@ -449,5 +449,4 @@
             dateScale.setRange(minval, maxval);
         }
-
 
         // Now the colors for all the points will be assigned
@@ -719,5 +718,5 @@
     }
 
-   /**
+    /**
      * Draw GPX lines by using alpha blending
      * @param g               the common draw object to use
@@ -853,23 +852,4 @@
         // transform into lookup table
         return colorTable;
-    }
-
-    /**
-     * Creates a colormap by using a static color map with 1..n colors (RGB 0.0 ..1.0)
-     * @param data array of multiple RGB color [n][3]
-     * @return a dynamic list of color objects
-     */
-    protected static Color[] createColorFromRawArray(double[][] data) {
-
-        // create the array
-        Color[] color = new Color[ data.length ];
-
-        for (int k = 0; k < data.length; k++) {
-           // cast an map to linear array
-           color[k] = new Color((float) data[k][0], (float) data[k][1], (float) data[k][2]);
-        }
-
-        // forward
-        return createColorLut(color);
     }
 
Index: /trunk/test/unit/org/openstreetmap/josm/gui/mappaint/MapCSSRendererTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/gui/mappaint/MapCSSRendererTest.java	(revision 11435)
+++ /trunk/test/unit/org/openstreetmap/josm/gui/mappaint/MapCSSRendererTest.java	(revision 11436)
@@ -65,5 +65,5 @@
      */
     @Parameters
-    public static Collection<Object[]> testRuns() {
+    public static Collection<Object[]> runs() {
         return Stream.of(
                 /** Tests for StyledMapRenderer#drawNodeSymbol */
@@ -89,5 +89,5 @@
      */
     @Test
-    public void render() throws Exception {
+    public void testRender() throws Exception {
         // load the data
         DataSet dataSet = testConfig.getOsmDataSet();