Parse xml file, rename tag and save it again

I have a pretty big xml file and need to change some of it, this is a snippet of how it looks

<CMPDN>
<ROOT_PRODUKTE>
    <PRODUKT name="00010000040">
        <BEZIEHUNGEN>
            <BEZIEHUNGSTYP name="ZBH2BIKE">
                <PRODUKT name="78104974100" id="1001049290">
                    <RELATEDARTICLES>
                        <RELATEDARTICLE name="F6101M0" id="1000264817"/>
                    </RELATEDARTICLES>
                </PRODUKT>
            </BEZIEHUNGSTYP>
        </BEZIEHUNGEN>
    </PRODUKT>
</ROOT_PRODUKTE>

This is as said just a snippet. I used jxb to convert a xsd file into java classes so now I was able to modify the data.

The problem comes when I want to rename one of the tags, and not just any tag. I want to rename the inner PRODUKT tag to PRODUKT_FIT like this:

<CMPDN>
<ROOT_PRODUKTE>
    <PRODUKT name="00010000040">
        <BEZIEHUNGEN>
            <BEZIEHUNGSTYP name="ZBH2BIKE">
                <PRODUKT_FIT name="78104974100" id="1001049290">
                    <RELATEDARTICLES>
                        <RELATEDARTICLE name="F6101M0" id="1000264817"/>
                    </RELATEDARTICLES>
                </PRODUKT_FIT>
            </BEZIEHUNGSTYP>
        </BEZIEHUNGEN>
    </PRODUKT>
</ROOT_PRODUKTE>

Now I have tried to create 3 new classes BEZIEHUNGEN,BEZIEHUNGSTYPand PRODUKT_FIT and I changed the definition for the class PRDUKT as seen here

public class PRODUKT {
@XmlElements({
    @XmlElement(name = "ATTRIBUTE", type = ATTRIBUTE.class),
    @XmlElement(name = "BEZIEHUNGEN", type = io.github.sumsar1812.models.write.BEZIEHUNGEN.class),
    @XmlElement(name = "BEZIEHUNGEN", type = BEZIEHUNGEN.class),
    @XmlElement(name = "KLASSEN", type = KLASSEN.class),
    @XmlElement(name = "LAENDER", type = LAENDER.class),
    @XmlElement(name = "MEDIENELEMENTE", type = MEDIENELEMENTE.class),
    @XmlElement(name = "PREISE", type = PREISE.class),
    @XmlElement(name = "RELATEDARTICLES", type = RELATEDARTICLES.class),
    @XmlElement(name = "TEXTELEMENTE", type = TEXTELEMENTE.class),
    @XmlElement(name = "PARENT_NAME", type = PARENTNAME.class),
})

where the models.write package contains the new 3 classes.

The PRODUKT_FIT class is shown below:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
        "attributeOrBEZIEHUNGENOrKLASSEN"
})
@XmlRootElement(name = "PRODUKT_FIT")
public class PRODUKT_FIT {

    @XmlElements({
            @XmlElement(name = "ATTRIBUTE", type = ATTRIBUTE.class),
            @XmlElement(name = "BEZIEHUNGEN", type = io.github.sumsar1812.models.write.BEZIEHUNGEN.class),
            @XmlElement(name = "KLASSEN", type = KLASSEN.class),
            @XmlElement(name = "LAENDER", type = LAENDER.class),
            @XmlElement(name = "MEDIENELEMENTE", type = MEDIENELEMENTE.class),
            @XmlElement(name = "PREISE", type = PREISE.class),
            @XmlElement(name = "RELATEDARTICLES", type = RELATEDARTICLES.class),
            @XmlElement(name = "TEXTELEMENTE", type = TEXTELEMENTE.class)
    })
    protected List<Object> attributeOrBEZIEHUNGENOrKLASSEN;
    @XmlAttribute(name = "name", required = true)
    protected String name;
/*getters and setters omitted */

So as far as I can see now a produkt should be able to contain both the read values of BEZIEHUNGEN and write values of BEZIEHUNGEN(containing a list of BEZIEHUNGSTYP and each of those containing a list of PRODUKT_FIT)

After reformatting some data I can see with the debugger that the data is formated correctly(RELATEDARTICLE is optional so thats why attributeOrBEZIEHUNGENOrKLASSEN is null)

But the problem is when i try to save the classes back to a file(as seen below) it is still named PRODUKT and not PRODUKT_FIT, all the other changes i have made to the data is saved correctly. any idea why this is ?

public void passRoot(String newFilename, CMPDN root) {
    try {
        File file = new File(newFilename);
        JAXBContext jaxbContext = JAXBContext.newInstance(CMPDN.class);
        Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
        jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
        jaxbMarshaller.marshal(root, file);

    } catch (JAXBException e) {
        e.printStackTrace();
    }
}

Edit So I tried using XSLT with some success, this is my stylesheet right now

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8"/>
<xsl:template match="@*|node()">
    <xsl:copy>
        <xsl:apply-templates select="@*|node()" />
    </xsl:copy>
</xsl:template>
<xsl:template match="CMPDN/ROOT_PRODUKTE/PRODUKT/BEZIEHUNGEN/BEZIEHUNGSTYP/PRODUKT">
    <PRODUKT_FIT>
        <xsl:apply-templates select="@*|node()" />
        <xsl:value-of select="."/>

    </PRODUKT_FIT>
</xsl:template>

This works but it adds blank lines below /RELATEDARTICLES> and </PRODUKT_FIT> So I tried adding <xsl:strip-space elements="*"/> but that made it all into one line, so I added omit-xml-declaration="yes" indent="yes" to the xsl:output but this only partly fixed it as now it looks like this:

which doesnt have the format as before, not sure why though?