Thread: Java org.w3c.dom.Document.normalize() isn't working as expected

I have the following 2 XML's:
<root><a><b>some text</b></a></root>
and
<root>
<a>
<b>some text</b>
</a>
</root>

I load them each in a different org.w3c.dom.Document: ctx1 and ctx2.
after I call
ctx1.normalize();
ctx2.normalize();
I try to check if element 'a' from ctx1 is equal with element 'a' from ctx2. I get failure because element 'a' from ctx2 is seen as containing 3 children, while 'a' element from ctx1 is seen to contain 1 child.

Why is this so? I think call to normalize should eliminate this problem but it doesn't.

N.B. I simplified the XML file for the sake of conciseness. My XML files are containing namespaces too. I think this shouldn't be a problem.

The full class bellow:

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.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
 
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSSerializer;
import org.xml.sax.SAXException;
 
public class XMLNormalizeMain {
 
	public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, XPathExpressionException {
 
		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
		DocumentBuilder db = dbf.newDocumentBuilder();
		InputStream is1 = Thread.currentThread().getContextClassLoader().getResourceAsStream("ctx1.xml");
		InputStream is2 = Thread.currentThread().getContextClassLoader().getResourceAsStream("ctx2.xml");
		Document ctx1 = db.parse(is1);
		Document ctx2 = db.parse(is2);
 
		ctx1.normalize();
		ctx2.normalize();
 
		XPathFactory xPathFactory = XPathFactory.newInstance();
		XPath xPath = xPathFactory.newXPath();
 
		Element a1 = (Element) getElement(ctx1, xPath, "/root/a");
		Element a2 = (Element) getElement(ctx2, xPath, "/root/a");
		System.out.println("a1: " + nodeToString(ctx1, a1));
		System.out.println("a2: " + nodeToString(ctx2, a2));
		System.out.println(a1.isEqualNode(a2));
 
 
	}
 
	private static Node getElement(Node e, XPath xpath, String path) throws XPathExpressionException {
 
		XPathExpression expr = xpath.compile(path);
		return (Node) expr.evaluate(e, XPathConstants.NODE);
 
	}
 
	private static String nodeToString(Document ctx, Node n) {
 
		DOMImplementationLS domImplLS = (DOMImplementationLS) ctx.getImplementation();
		LSSerializer serializer = domImplLS.createLSSerializer();
 
		return serializer.writeToString(n);
 
	}
 
}

XML for ctx1:

HTML Code:

<?xml version="1.0" encoding="UTF-8"?>
<root>
	<a>
		<b>some text here</b>
	</a>
</root>

XML for ctx2:

HTML Code:

<?xml version="1.0" encoding="UTF-8"?>
<root><a><b>some text here</b></a></root>