Index: applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/MapillaryDataTest.java
===================================================================
--- applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/MapillaryDataTest.java	(revision 31882)
+++ applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/MapillaryDataTest.java	(revision 31909)
@@ -45,5 +45,5 @@
 
     this.data = new MapillaryData();
-    this.data.add(new ConcurrentSkipListSet(this.seq.getImages()));
+    this.data.add(new ConcurrentSkipListSet<>(this.seq.getImages()));
   }
 
@@ -60,8 +60,8 @@
     this.data.add(this.img1);
     assertEquals(1, this.data.getImages().size());
-    this.data.add(new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[] { this.img2,
+    this.data.add(new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[] { this.img2,
         this.img3 })));
     assertEquals(3, this.data.getImages().size());
-    this.data.add(new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[] { this.img3,
+    this.data.add(new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[] { this.img3,
         this.img4 })));
     assertEquals(4, this.data.getImages().size());
Index: applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/gui/MapillaryPreferenceSettingTest.java
===================================================================
--- applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/gui/MapillaryPreferenceSettingTest.java	(revision 31882)
+++ applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/gui/MapillaryPreferenceSettingTest.java	(revision 31909)
@@ -56,5 +56,5 @@
   }
 
-  private Object getPrivateField(MapillaryPreferenceSetting object, String name) throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, SecurityException {
+  private static Object getPrivateField(MapillaryPreferenceSetting object, String name) throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, SecurityException {
     Field field = object.getClass().getDeclaredField(name);
     field.setAccessible(true);
Index: applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/history/MapillaryRecordTest.java
===================================================================
--- applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/history/MapillaryRecordTest.java	(revision 31882)
+++ applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/history/MapillaryRecordTest.java	(revision 31909)
@@ -16,5 +16,4 @@
 import org.openstreetmap.josm.plugins.mapillary.MapillaryImage;
 import org.openstreetmap.josm.plugins.mapillary.MapillaryLayer;
-import org.openstreetmap.josm.plugins.mapillary.history.MapillaryRecord;
 import org.openstreetmap.josm.plugins.mapillary.history.commands.CommandDelete;
 import org.openstreetmap.josm.plugins.mapillary.history.commands.CommandImport;
@@ -56,16 +55,16 @@
   public void commandTest() {
     MapillaryCommand cmd12 = new CommandMove(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
             0.1, 0.1);
     MapillaryCommand cmd23 = new CommandMove(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img2, this.img3})),
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img2, this.img3})),
             0.1, 0.1);
     MapillaryCommand cmd13 = new CommandMove(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img3})),
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img3})),
             0.1, 0.1);
     MapillaryCommand cmd1 = new CommandMove(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1})), 0.1, 0.1);
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1})), 0.1, 0.1);
     MapillaryCommand cmd31 = new CommandMove(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img3, this.img1})),
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img3, this.img1})),
             0.2, 0.2);
     this.record.addCommand(cmd12);
@@ -112,8 +111,8 @@
   public void commandMoveTest() {
     CommandMove cmd1 = new CommandMove(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
             0.1, 0.1);
     CommandMove cmd2 = new CommandMove(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
             0.1, 0.1);
 
@@ -146,8 +145,8 @@
   public void commandTurnTest() {
     CommandTurn cmd1 = new CommandTurn(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
             0.2);
     CommandTurn cmd2 = new CommandTurn(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2})),
             0.1);
 
@@ -253,7 +252,7 @@
 
     CommandDelete cmd1 = new CommandDelete(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1})));
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1})));
     CommandDelete cmd2 = new CommandDelete(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img2, this.img3})));
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img2, this.img3})));
 
     this.record.addCommand(join1);
@@ -264,5 +263,5 @@
             .getData()
             .add(
-                    new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2,
+                    new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2,
                             this.img3})));
 
@@ -286,7 +285,7 @@
 
     CommandImport cmd1 = new CommandImport(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img1})));
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img1})));
     CommandImport cmd2 = new CommandImport(
-            new ConcurrentSkipListSet(Arrays.asList(new MapillaryAbstractImage[]{this.img2, this.img3})));
+            new ConcurrentSkipListSet<>(Arrays.asList(new MapillaryAbstractImage[]{this.img2, this.img3})));
 
     this.record.addCommand(cmd1);
Index: applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/traffico/TrafficoSignElementTest.java
===================================================================
--- applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/traffico/TrafficoSignElementTest.java	(revision 31882)
+++ applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/traffico/TrafficoSignElementTest.java	(revision 31909)
@@ -1,5 +1,6 @@
 package org.openstreetmap.josm.plugins.mapillary.traffico;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 
 import java.awt.Color;
@@ -21,5 +22,5 @@
   @Test(expected=IllegalArgumentException.class)
   public void testNullColor() {
-    new TrafficoSignElement('\ufeed', null);
+    assertNotNull(new TrafficoSignElement('\ufeed', null));
   }
 
Index: applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/utils/MapillaryURLTest.java
===================================================================
--- applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/utils/MapillaryURLTest.java	(revision 31882)
+++ applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/utils/MapillaryURLTest.java	(revision 31909)
@@ -183,5 +183,5 @@
   }
 
-  private void assertUrlEquals(URL actualUrl, String expectedBaseUrl, String... expectedParams) {
+  private static void assertUrlEquals(URL actualUrl, String expectedBaseUrl, String... expectedParams) {
     assertEquals(expectedBaseUrl, actualUrl.toString().substring(0, actualUrl.toString().indexOf('?')));
     String[] actualParams = actualUrl.getQuery().split("&");