Pb java

public class recherche extends HttpServlet{

public static XQLResult Result,Resultat;
public static String requeteXQL,requeteXQL2;
public static final String Fichier_xml ="arbre.xml";

public void doPost(HttpServletRequest req, HttpServletResponse res)
throws ServletException,IOException{

res.setContentType("text/html");
PrintWriter out=res.getWriter();
String motcle=req.getParameter("mot");
out.print("<HTML>");
out.print("<TITLE>Résultat de la recherche</TITLE>");
out.print("<HEAD></HEAD><BODY>");

try
{

DOMParser dom = new DOMParser();
dom.parse(Fichier_xml);
Document doc = dom.getDocument();
requeteXQL="//composant/mots_clefs";
Result = XQL.execute(requeteXQL, doc);
int Nbmot = Result.getLength();

out.print(""+Nbmot);
}catch(Exception e){}

}
}