import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.xml.sax.InputSource;

public class Main {
    public static void main(String[] args) throws Exception {
        String xml = "<?xml version=\"1.0\" encoding=\"iso-8859-1\" ?>\r\n" + //
                "<REPOSITORY xmlns:LIBRARY = \"http://w...content-available-to-author-only...s.org/LIBRARY/2.0/\" xmlns:xsi = \"http://w...content-available-to-author-only...3.prg/2001/XMLSchema-instance\"  xsi:schemaLocation = \"http://w...content-available-to-author-only...s.org/LIBRARY/2.0/ http://w...content-available-to-author-only...s.org/LIBRARY/2.0/LIBRARY-PHM.xsd\">\r\n" + // 
                "<repository>Test</repository>\r\n" + //
                "<records><record>\r\n" + //
                "<ejemplar>\r\n" + //
                "<library_book:book \r\n" + // 
                "    xmlns:library_book=\"http://w...content-available-to-author-only...c.es/LIBRARY/book/\"\r\n" + // 
                "    xmlns:book=\"http://w...content-available-to-author-only...c.es/LIBRARY/book/\"\r\n" + //
                "    xmlns:bookAssets=\"http://w...content-available-to-author-only...c.es/LIBRARY/book/\"\r\n" + // 
                "    xmlns:bookAsset=\"http://w...content-available-to-author-only...c.es/LIBRARY/book/\"\r\n" + //
                "    xmlns:xsi=\"http://w...content-available-to-author-only...3.org/2001/XMLSchema-instance\"\r\n" + //
                "    xsi:schemaLocation=\"http://w...content-available-to-author-only...c.es/LIBRARY/book/ http://w...content-available-to-author-only...c.es/LIBRARY/replacement/book.xsd\">\r\n" + // 
                "<book:bookAssets count=\"1\">\r\n" + //
                "<book:bookAsset nasset=\"1\">\r\n" + //
                "<book:bookAsset.id>value1</book:bookAsset.id>\r\n" + // 
                "<book:bookAsset.event>\r\n" + //
                "<book:bookAsset.event.id>value2</book:bookAsset.event.id>\r\n" + // 
                "</book:bookAsset.event>\r\n" + //
                "</book:bookAsset>\r\n" + //
                "</book:bookAssets>\r\n" + //
                "</library_book:book>\r\n" + //
                "</ejemplar>\r\n" + //
                "</record></records>\r\n" + // 
                "</REPOSITORY>";
        // Standard of reading a XML file
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(true);
        DocumentBuilder builder;
        Document doc = null;
        XPathExpression expr = null;
        builder = factory.newDocumentBuilder();
        doc = builder.parse(new InputSource(new StringReader(xml)));
        // Create a XPathFactory
        XPathFactory xFactory = XPathFactory.newInstance();
        // Create a XPath object
        XPath xpath = xFactory.newXPath();
        expr = xpath.compile("//*[local-name()='bookAsset.event.id']/text()");
        Object result = expr.evaluate(doc, XPathConstants.STRING);
        System.out.println("RESULT=" + result);
    }
}