bug fix when there's no children nor value

core/src/main/java/jenkins/util/xstream/XStreamDOM.java

@@ -377,7 +377,7 @@ public class XStreamDOM {
             if (dom.value!=null)
                 w.setValue(dom.value);
             else {
-                for (XStreamDOM c : dom.children) {
+                for (XStreamDOM c : Util.fixNull(dom.children)) {
                     marshal(c, w, context);
                 }
             }

core/src/test/java/jenkins/util/xstream/XStreamDOMTest.java

@@ -80,4 +80,11 @@ public class XStreamDOMTest extends TestCase {
         assertEquals(IOUtils.toString(getClass().getResourceAsStream("XStreamDOMTest.data1.xml")).trim(),xml.trim());
     }
 
+    public void testNoChild() {
+        String[] in = new String[0];
+        XStreamDOM dom = XStreamDOM.from(xs, in);
+        System.out.println(xs.toXML(dom));
+        String[] out = dom.unmarshal(xs);
+        assertEquals(in.length, out.length);
+    }
 }