Download file in JSF appliccation

Hi,

In my application developed by JSF2.0 + Richfaces3.3.3 + Tomcat6.0.29.

I maintain my log file into this location : E:\Tomcat-6.0.29\logs\project.log
My tomcat(webapps) Location : E:\Tomcat-6.0.29\Tomcat 6.0\webapps

In my page have one button. When i click that button i want to download that log file, without change the content and filename.
But in my code automatically generate file name. like E-_Tomcat-6.0.29_logs_project.log and also content is empty.

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %>
<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %>
<%@ taglib uri="http://richfaces.org/a4j" prefix="a4j"%>
<%@ taglib uri="http://richfaces.org/rich" prefix="rich"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">

<f:view>
    <html>
        <head>
            <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
            <title>JSP Page</title>
        </head>
        <body>
            <h:form id="downloadForm" binding="#{Download.initForm}">

<a4j:outputPanel id="downloadOutputPanel">
                       
                        <h:commandButton value="Download Log file"  action="#{Download.downloadButtonAction}"/>                                          
                      
                    </a4j:outputPanel>
                
            </h:form>
        </body>
    </html>
</f:view>

and

import java.io.File;
import java.io.IOException;
import java.util.zip.ZipOutputStream;
import javax.faces.component.html.HtmlForm;
import javax.faces.context.FacesContext;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class Download {

private HtmlForm initForm;
    private String fileLocaation;

public   Download()
   {        
        HttpSession httpSession = getHttpSession();
        fileLocaation = httpSession.getServletContext().getRealPath("");

String webAppsLocation = fileLocaation.substring(0, fileLocaation.indexOf("webapps") - 1);
        String tomcatLocation = webAppsLocation.substring(0, webAppsLocation.lastIndexOf(File.separator));

fileLocaation  = tomcatLocation + File.separator + "logs" + File.separator + "project.log";       
   }

private HttpSession getHttpSession() {
        HttpSession httpSession = null;
        FacesContext facesContext = FacesContext.getCurrentInstance();
        httpSession = (HttpSession) facesContext.getExternalContext().getSession(false);
        return httpSession;
    }

public String downloadButtonAction() throws IOException {

FacesContext fc = FacesContext.getCurrentInstance();
        HttpServletResponse response = (HttpServletResponse) fc.getExternalContext().getResponse();
        ServletOutputStream out = response.getOutputStream();

ZipOutputStream zipout = new ZipOutputStream(out);

response.setContentType("application/octet-stream");
        response.addHeader("Content-Disposition", "attachment; filename=\"" + fileLocaation + "\"");
        out.flush();

try {
            if (out != null) {
                out.close();
            }
            FacesContext.getCurrentInstance().responseComplete();
        } catch (IOException e) {
        }
        
        return null;
    }
   
    public HtmlForm getInitForm() {       
        return initForm;
    }

public void setInitForm(HtmlForm initForm) {
        this.initForm = initForm;
    }
  
    public String getFileLocaation() {
        return fileLocaation;
    }
  
    public void setFileLocaation(String fileLocaation) {
        this.fileLocaation = fileLocaation;
    }  
   
}

Help me.
Thanks in advance.