Index: /trunk/src/org/openstreetmap/josm/gui/MapScaler.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/MapScaler.java	(revision 10078)
+++ /trunk/src/org/openstreetmap/josm/gui/MapScaler.java	(revision 10079)
@@ -26,6 +26,6 @@
     private final NavigatableComponent mv;
 
-    private final static int PADDING_LEFT = 5;
-    private final static int PADDING_RIGHT = 50;
+    private static final int PADDING_LEFT = 5;
+    private static final int PADDING_RIGHT = 50;
 
     /**
@@ -121,5 +121,5 @@
          * @param width The width of the mark.
          */
-        public TickMarks(double dist100Pixel, int width) {
+        TickMarks(double dist100Pixel, int width) {
             this.dist100Pixel = dist100Pixel;
             lineDistance = dist100Pixel * width / 100;
Index: /trunk/src/org/openstreetmap/josm/io/CertificateAmendment.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/CertificateAmendment.java	(revision 10078)
+++ /trunk/src/org/openstreetmap/josm/io/CertificateAmendment.java	(revision 10079)
@@ -96,5 +96,6 @@
             byte[] sha = md.digest(certBytes);
             if (!SHA_HASHES[i].equals(Utils.toHexString(sha)))
-                throw new RuntimeException(tr("Error adding certificate {0} - hash mismatch. Expected {1}, was {2}", CERT_AMEND[i], SHA_HASHES[i], Utils.toHexString(sha)));
+                throw new RuntimeException(tr("Error adding certificate {0} - hash mismatch. Expected {1}, was {2}",
+                        CERT_AMEND[i], SHA_HASHES[i], Utils.toHexString(sha)));
 
             ByteArrayInputStream certIS = new ByteArrayInputStream(certBytes);
Index: /trunk/test/unit/org/openstreetmap/josm/gui/TableCellRendererTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/gui/TableCellRendererTest.java	(revision 10078)
+++ /trunk/test/unit/org/openstreetmap/josm/gui/TableCellRendererTest.java	(revision 10079)
@@ -32,11 +32,12 @@
  * value to check if a NPE is thrown.
  *
- * @see #6301
+ * @see <a href="https://josm.openstreetmap.de/ticket/6301">#6301</a>
  */
 public class TableCellRendererTest {
 
-    // list of classes that cannot be easily tested and are verified manually
+    // list of classes that cannot be easily tested and are verified either manually or another unit tests
     private static final Collection<String> SKIP_TEST = Arrays.asList(
-        "org.openstreetmap.josm.gui.dialogs.FilterDialog$BooleanRenderer"
+        "org.openstreetmap.josm.gui.dialogs.FilterDialog$BooleanRenderer",
+        "org.openstreetmap.josm.gui.dialogs.relation.SelectionTableCellRenderer"
     );
 
@@ -49,4 +50,7 @@
     }
 
+    /**
+     * Unit test of all table cell renderers against null values.
+     */
     @Test
     public void tableCellRendererTest() {