JAVA loop through children of Nodelist

I have an XML file call it (FromThis.xml) with sample data see below:

I want to read from the file(FromThis.xml) , store the values in variable then use those variable while creating a second XML file(ToThis.xml).

Brief description of my scenario[ I will read values from XML file(FromThis.xml) first and store them in a variables. Then I will use the variables to update the second xml file which is (ToThis.xml .I later use this xml to create some JSON file in some specified format.) I have been working with this but later we need to send array of elements in (FromThis.xml). From my code below i can only get the first array element but i want to loop through the elements, store them and use it to create the second xml (ToThis.xml)

(FromThis.xml)

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Root>
<ankomstDato>2020-08-20</ankomstDato>
<planlagtAntallPerUndergruppe>
<element>
<antall>67</antall>
<kode>SLAKTEGRIS</kode>
</element>
<element>
<antall>4</antall>
<kode>UNGSAU</kode>
</element>
</planlagtAntallPerUndergruppe>
</Root>

(ToThis.xml) Below xml is what i currently get.

<?xml version="1.0" encoding="UTF-8"?><map xmlns="http://www.w3.org/2005/xpath-functions">
<string key="ankomstDato">2020-08-20</string>
<array key="planlagtAntallPerUndergruppe">
<map>
<number key="antall">67</number>
<string key="kode">SLAKTEGRIS</string>
</map> 
</array>   
</map>

What i would like to get as the result is

<?xml version="1.0" encoding="UTF-8"?><map xmlns="http://www.w3.org/2005/xpath-functions">
<string key="ankomstDato">2020-08-20</string>
<array key="planlagtAntallPerUndergruppe">
<map>
<number key="antall">67</number>
<string key="kode">SLAKTEGRIS</string>
</map> 
<map>
<number key="antall">4</number>
<string key="kode">UNGSAU</string>
</map>
</array>   
</map>

Below is my Code

    import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import org.w3c.dom.Element;
//** */
public class SolutionXML2XmlFormat {
//Create Public Variables to store data
//**
public static String ankomstDato_value; //1
public static String[] planlagtAntallPerUndergruppe_antall_value = new String[6]; //
public static String[] planlagtAntallPerUndergruppe_kode_value = new String[6]; //
//+++
public void Xml2JavaObject(String FromThis){
//read the xml(TheXMLPath) and store values in variables
// Boolean and numbers should be having values for string use " " if empty
try {
File file = new File(FromThis);
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory
.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.parse(file);
document.getDocumentElement().normalize();
System.out.println("Root element :" + document.getDocumentElement().getNodeName());
System.out.println("------------------------ \n");
//1 . ankomstDato
String ankomstDato = document.getElementsByTagName("ankomstDato").item(0).getTextContent();
ankomstDato_value = ankomstDato;
//end ankomstDato
NodeList planlagtAntallPerUndergruppe= document.getElementsByTagName("planlagtAntallPerUndergruppe");
for (int temp = 0; temp < planlagtAntallPerUndergruppe.getLength(); temp++) {                
Node nNode = planlagtAntallPerUndergruppe.item(temp);
System.out.println("\n Current Elements :" + planlagtAntallPerUndergruppe.getLength());
System.out.println("\n No. of  Element :" + temp);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element eElement = (Element) nNode;
String element18 = eElement.getElementsByTagName("antall").item(0).getTextContent();                    
planlagtAntallPerUndergruppe_antall_value[temp] = element18;  
String element19 = eElement.getElementsByTagName("kode").item(0).getTextContent();                    
planlagtAntallPerUndergruppe_kode_value[temp] = element19;               
} 
} 
} catch (Exception e) {
e.printStackTrace();
}
//Call method to write values
Write2XMLfile();
}
public void Write2XMLfile(){
XPathFactory xpathFact = XPathFactory.newInstance();
XPath xpath = xpathFact.newXPath();
try {
//
String filepath = "E:/utils/Tothis.xml";
//
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.parse(filepath);
// 1. ankomstDato
Node ankomstDato = (Node) xpath.evaluate("(/map/string[@key='ankomstDato'])[1]", doc, XPathConstants.NODE);
ankomstDato.setTextContent(ankomstDato_value );
// End ankomstDato
//2.  planlagtAntallPerUndergruppe **************************
System.out.println("\n This is second" );
Node planlagtAntallPerUndergruppe = (Node) xpath.evaluate("/map/array[@key='planlagtAntallPerUndergruppe']/*", doc, XPathConstants.NODE);
if(null != planlagtAntallPerUndergruppe) {
NodeList nodeList = planlagtAntallPerUndergruppe.getChildNodes();
for (int i = 0;null!=nodeList && i < nodeList.getLength(); i++) {
Node nod = nodeList.item(i);
//System.out.println("\n");
if(nod.getNodeType() == Node.ELEMENT_NODE){
NodeList arrayElements_18 = (NodeList) xpath.evaluate("/map/array[@key='planlagtAntallPerUndergruppe']/*", doc, XPathConstants.NODESET);
//System.out.println("\n number of elements" + arrayElements_18.getLength());
for (int j = 0; j < arrayElements_18.getLength(); j++) {
//.  antall
Node antall = (Node) xpath.evaluate("(/map/array/map/number[@key='antall'])[1]", doc, XPathConstants.NODE);
antall.setTextContent(planlagtAntallPerUndergruppe_antall_value[j]);
// end antall
//.  kode
Node kode = (Node) xpath.evaluate("(/map/array/map/string[@key='kode'])[1]", doc, XPathConstants.NODE);
kode.setTextContent(planlagtAntallPerUndergruppe_kode_value[j]);
//System.out.println("\n\n antall: " + planlagtAntallPerUndergruppe_antall_value[j]);
// end kode                       
}                    
}
}
}
// end array planlagtAntallPerUndergruppe
// write the content into xml file
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File(filepath));
transformer.transform(source, result);
System.out.println("Done Updating The Api_XML_Format.xml");
} catch (ParserConfigurationException pce) {
pce.printStackTrace();
} catch (TransformerException tfe) {
tfe.printStackTrace();
} catch (IOException ioe) {
ioe.printStackTrace();
} catch (SAXException sae) {
sae.printStackTrace();
} catch (XPathExpressionException xee) {
xee.printStackTrace();
}
}
}

as per the given code, planlagtAntallPerUndergruppe NodeList size is a one. because you select the <planlagtAntallPerUndergruppe> element.

NodeList planlagtAntallPerUndergruppe = document.getElementsByTagName("planlagtAntallPerUndergruppe");

hence, in the for loop, declared arrays collect the first <element> values only from FromThis.xml file.

<element>
<antall>67</antall>
<kode>SLAKTEGRIS</kode>
</element>

Solution

get the <element> NodeList into planlagtAntallPerUndergruppe as follows,

NodeList planlagtAntallPerUndergruppe = document.getElementsByTagName("element");