XML in Java: Print every node once (instead of multiple times)

I have the following xml-structure (in my XML-file there are way more nodes but I think that's enough for demonstration):

<log>
    <published>2014-03-28T15:28:36.646Z</published>
    <actor>
        <objectType>person</objectType>
        <id>e1b8948f-321e-78ca-d883-80500aae71b5</id>
        <displayName>anonymized</displayName>
    </actor>
    <verb>update</verb>
    <object>
        <objectType>concept</objectType>
        <id>a1ad6ace-c722-ffa9-f58e-b4169acdb4e3</id>
        <content>time</content>
    </object>
</log>

The following method prints all nodes:

public static void parseRecursive(Node node, Node parent) {

    NodeList childs = node.getChildNodes();
    if (parent != null) {
        toXes.createString(parent.getNodeName(), "");
    }
    for (int i = 0; i < childs.getLength(); i++) {
        if (childs.getLength() > 1) {
            parseRecursive(childs.item(i), node);
        } else {
            toXes.createNestedString(node.getNodeName(), childs.item(i).getNodeValue(), "string");
            System.out.println("PARENT: " + parent.getNodeName());

            System.out.println("CHILD-KEY: " + node.getNodeName());

            System.out.println("CHILD-VALUE: " + childs.item(i).getNodeValue());
            System.out.println("--------------------------------------------");
        }
    }
}

The Output look like this (again shortened, it is the Output of my "createString / createNestedString"-methods):

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<log xes.features="" xes.version="2.0">
  <trace>
    <event>
      <string key="log" value=""/>
      <string key="log" value="">
        <string key="published" value="2014-03-28T15:28:36.646Z"/>
      </string>
      <string key="log" value=""/>
      <string key="log" value=""/>
      <string key="actor" value=""/>
      <string key="actor" value="">
        <string key="objectType" value="person"/>
      </string>
      <string key="actor" value=""/>
      <string key="actor" value="">
        <string key="id" value="e1b8948f-321e-78ca-d883-80500aae71b5"/>
      </string>
      <string key="actor" value=""/>
      <string key="actor" value="">
        <string key="displayName" value="anonymized"/>
      </string>
      <string key="actor" value=""/>
      ...

My problem is that I don't know why some nodes are printed multiple times. I expect that for example "log" and "actor" just appears once - and the child-nodes of them are appended once, too (indeed they will be appended only once as you see in the output... but the parent nodes are printed way to often) . Is there a quick hack how I can make this?

CreateString just appends a String-Node to the log element and createNestedString just appends a child node to the parent node element.

EDIT

//Appends the <string>-element to the <log>-element.
public static void createString(String key, String value) {
    stringElement = doc.createElement("string");
    eventElement.appendChild(stringElement);

    // attributes of "string"-element in .xes - key
    attr = doc.createAttribute("key");
    attr.setValue(key);
    stringElement.setAttributeNode(attr);

    // attributes of "string"-element in .xes - value
    attr = doc.createAttribute("value");
    attr.setValue(value);
    stringElement.setAttributeNode(attr);
}

//Asks whether the attribute is nested.
//Valid params: log, event, ...
public static void createNestedString(String key, String value, String nested) {
    Element stringElement2 = doc.createElement("string");
    if (nested.equals("log")) {
        logElement.appendChild(stringElement2);
    } else if (nested.equals("global")) {
        globalElement.appendChild(stringElement2);
    } else if (nested.equals("trace")) {
        traceElement.appendChild(stringElement2);
    } else if (nested.equals("event")) {
        eventElement.appendChild(stringElement2);
    } else if (nested.equals("int")) {
        intElement.appendChild(stringElement2);
    } else if (nested.equals("date")) {
        dateElement.appendChild(stringElement2);
    } else if (nested.equals("string")) {
        stringElement.appendChild(stringElement2);
    } else if (nested.equals("float")) {
        floatElement.appendChild(stringElement2);
    } else if (nested.equals("boolean")) {
        booleanElement.appendChild(stringElement2);
    } else if (nested.equals("id")) {
        idElement.appendChild(stringElement2);
    } else if (nested.equals("list")) {
        listElement.appendChild(stringElement2);
    } else if (nested.equals("container")) {
        containerElement.appendChild(stringElement2);
    } else {
        System.err.println("ERROR: Could not append nested <string> to another element.");
    }

    // attributes of "string"-element in .xes - key
    attr = doc.createAttribute("key");
    attr.setValue(key);
    stringElement2.setAttributeNode(attr);

    // attributes of "string"-element in .xes - value
    attr = doc.createAttribute("value");
    attr.setValue(value);
    stringElement2.setAttributeNode(attr);
}