Index: trunk/test/unit/org/openstreetmap/josm/gui/help/HelpBrowserTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/gui/help/HelpBrowserTest.java	(revision 14803)
+++ trunk/test/unit/org/openstreetmap/josm/gui/help/HelpBrowserTest.java	(revision 14807)
@@ -61,4 +61,9 @@
 
             @Override
+            public void setUrl(String url) {
+                this.url = url;
+            }
+
+            @Override
             public HelpBrowserHistory getHistory() {
                 return history;
Index: trunk/test/unit/org/openstreetmap/josm/gui/help/HyperlinkHandlerTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/gui/help/HyperlinkHandlerTest.java	(revision 14807)
+++ trunk/test/unit/org/openstreetmap/josm/gui/help/HyperlinkHandlerTest.java	(revision 14807)
@@ -0,0 +1,48 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.help;
+
+import static org.junit.Assert.assertNotNull;
+
+import java.io.StringReader;
+
+import javax.swing.event.HyperlinkEvent;
+import javax.swing.text.Element;
+import javax.swing.text.html.HTMLDocument;
+import javax.swing.text.html.HTMLEditorKit;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.openstreetmap.josm.gui.widgets.JosmEditorPane;
+import org.openstreetmap.josm.testutils.JOSMTestRules;
+
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+
+/**
+ * Unit tests of {@link HyperlinkHandler} class.
+ */
+public class HyperlinkHandlerTest {
+
+    /**
+     * Setup tests
+     */
+    @Rule
+    @SuppressFBWarnings(value = "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
+    public JOSMTestRules test = new JOSMTestRules().preferences();
+
+    /**
+     * Non-regression test for ticket <a href="https://josm.openstreetmap.de/ticket/17338">#17338</a>.
+     * @throws Exception if an error occurs
+     */
+    @Test
+    public void testTicket17338() throws Exception {
+        JosmEditorPane help = new JosmEditorPane();
+        HTMLEditorKit htmlKit = new HTMLEditorKit();
+        HTMLDocument htmlDoc = (HTMLDocument) htmlKit.createDefaultDocument();
+        htmlKit.read(new StringReader("<a id=\"foo\" href=\"null#WrongAnchor\">bar</a>"), htmlDoc, 0);
+        Element element = htmlDoc.getElement("foo");
+        assertNotNull(element);
+        help.setDocument(htmlDoc);
+        new HyperlinkHandler(HelpBrowserTest.newHelpBrowser(), help)
+            .hyperlinkUpdate(new HyperlinkEvent(this, HyperlinkEvent.EventType.ACTIVATED, null, null, element));
+    }
+}