/Workbook/Worksheet/Table/Row/Cell

using System;
using System.Xml;

namespace DumpCells
{
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFile = @"..\..\Book1.xml";
            XmlDocument xmlDocument = new XmlDocument();
            xmlDocument.Load(xmlFile);
            XmlTextReader xmlTextReader = new XmlTextReader(xmlFile);
            XmlNamespaceManager xmlNamespaceManager = new XmlNamespaceManager(xmlTextReader.NameTable);

            xmlNamespaceManager.AddNamespace("default_ns", "urn:schemas-microsoft-com:office:spreadsheet");
            xmlNamespaceManager.AddNamespace("x", "urn:schemas-microsoft-com:office:excel");
            xmlNamespaceManager.AddNamespace("ss", "urn:schemas-microsoft-com:office:spreadsheet");

            XmlNodeList xmlNodes = xmlDocument.SelectNodes("/default_ns:Workbook/ss:Worksheet/ss:Table/default_ns:Row/ss:Cell", xmlNamespaceManager);
            for (int i =  0 ; i < xmlNodes.Count; i++)
            {
                Console.WriteLine("InnerText: {0}", xmlNodes[i].ChildNodes[ 0 ].InnerText);                
            }
        }
    }
}

import java.util.Iterator;
import javax.xml.xpath.*; // for XPath, XPathFactory
import javax.xml.namespace.*;
import javax.xml.*;
import org.w3c.dom.NodeList; // for NodeList
import org.xml.sax.*; // for InputSource

class MyNamespaceContext implements NamespaceContext
{
	public String getNamespaceURI(String prefix)
	{
		if (prefix.equals("x"))
			return "urn:schemas-microsoft-com:office:excel";
		else if (prefix.equals("o"))
			return "urn:schemas-microsoft-com:office:office";
		else if (prefix.equals("ss"))
			return "urn:schemas-microsoft-com:office:spreadsheet";
		else if (prefix.equals("html"))
			return "http://www.w3.org/TR/REC-html40";
		else
			return "urn:schemas-microsoft-com:office:spreadsheet";
	}

	public String getPrefix(String namespace)
	{
		if (namespace.equals("urn:schemas-microsoft-com:office:excel"))
			return "x";
		else if (namespace.equals("urn:schemas-microsoft-com:office:office"))
			return "o";
		else if (namespace.equals("urn:schemas-microsoft-com:office:spreadsheet"))
			return "ss";
		else if (namespace.equals("http://www.w3.org/TR/REC-html40"))
			return "html";
		else
			return null;
	}

	public Iterator getPrefixes(String namespace)
	{
		return null;
	}
}  

public class sample
{
	public static void main(String[] args) throws XPathExpressionException
	{
		XPath xpath = XPathFactory.newInstance().newXPath();
		String expression = "/default_ns:Workbook/ss:Worksheet/ss:Table/default_ns:Row/ss:Cell";
		InputSource inputSource = new InputSource("Book1.xml");
		xpath.setNamespaceContext(new MyNamespaceContext());
		NodeList nodes = (NodeList)xpath.evaluate(expression, inputSource, XPathConstants.NODESET);
		for (int i =  0 ; i < nodes.getLength(); i++)
		{
			System.out.println(nodes.item(i).getTextContent());
		}
	}
}