Why are xmlns="" added to element in Java automatically?

I am creating an XML file using Java.
I created root node using createElemenNS() to createh root node with namespace.

Element root = doc.createElementNS("http://www.myorc.com/schemas", "InvConf");

Then I created a node using createElement() and added it to root node. This node is automatically added with namespace like below.

 Element invList = doc.createElement("InvList");
 root.appendChild(invList);

<InvConf xmlns="http://www.myorc.com/schemas">
   <InvList xmlns="">
   ...
   </InvList>
   <InvList xmlns="">
   ...
   </InvList>
   <InvList xmlns="">
   ...
   </InvList>
</InvConf>

How to avoid adding the namespace to child nodes ?
I want the final XML to be like the following

<InvConf xmlns="http://www.myorc.com/schemas">
   <InvList>
   ...
   </InvList>
   <InvList>
   ...
   </InvList>
   <InvList>
   ...
   </InvList>
</InvConf>

Found that issues is coming only when xmlparserv2.jar is in CLASSPATH. This is required by some parts for the application. How to resolve this ?

The xmlns="" were added because your child is not in a namespace, and your parent is. To change that, put it in the namespace at the time you create the element.
Change the

createElement("InvList");

To the correct namespace.

As pointed out in comments xmlns="" means that element doesn't have any namespace. E.g. from XML parser point of view following two documents are identical:

<ns:root xmlns:ns="http://namespace.com">
    <child/>
</ns:root>

and

<root xmlns="http://namespace.com">
    <child xmlns=""/>
</root>

To avoid creation of xmlns="" in elements not belonging to any namespace you can create prefix on upper level element:

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
DocumentBuilder db = dbf.newDocumentBuilder();
    
Document doc = db.newDocument();
Element root = doc.createElementNS("http://namespace.com", "root");
root.setPrefix("ns");
Element child = doc.createElementNS("", "child");
root.appendChild(child);
doc.appendChild(root);

This code will create following XML:

<ns:root xmlns:ns="http://namespace.com">
    <child/>
</ns:root>

Alternatively you can use following syntax to achieve same result:

Document doc = db.newDocument();
Element root = doc.createElementNS("http://namespace.com", "ns:root");
Element child = doc.createElementNS("", "child");
root.appendChild(child);
doc.appendChild(root);

When commenting out line root.setPrefix("ns"); or creating element without prefix (doc.createElementNS("http://namespace.com", "root");) following XML will be generated:

<root xmlns="http://namespace.com">
    <child xmlns=""/>
</root>