Top Most Google Contact Import Code. Enjoy Cheers :)

package com.blc.donate2mail.contactimport.action;

import static net.oauth.OAuth.HMAC_SHA1;
import static net.oauth.OAuth.OAUTH_SIGNATURE_METHOD;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;

import org.w3c.dom.Node;
import org.w3c.dom.Element;


import net.oauth.OAuthAccessor;
import net.oauth.OAuthConsumer;
import net.oauth.OAuthMessage;
import net.oauth.ParameterStyle;
import net.oauth.example.consumer.webapp.CookieConsumer;

/**
 
 * @author Siddhartha Mukherjee , */
public class GoogleContactsConsumer extends HttpServlet {
private static final String forwardTo = "/gmailContacts.jsp";
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
        OAuthConsumer consumer = null;
        try {
            consumer = CookieConsumer.getConsumer("googleContacts", getServletContext());
            OAuthAccessor accessor = CookieConsumer.getAccessor(request, response, consumer);
            // You can switch to a different signature method:
            accessor.consumer.setProperty(OAUTH_SIGNATURE_METHOD, HMAC_SHA1);
            // HMAC uses the access token secret as a factor,
            // and it's a little less compute-intensive than RSA.
            OAuthMessage message = accessor.newRequestMessage(OAuthMessage.GET,
                    "http://www.google.com/m8/feeds/contacts/default/full?updated-min=2010-03-16T00:00:00&max-results=1000", null);
            OAuthMessage result = CookieConsumer.CLIENT.invoke(message, ParameterStyle.AUTHORIZATION_HEADER);
            // Simply pass the data through to the browser:
           
            response.setContentType("text/html");
            InputStream in = result.getBodyAsStream();
            Set gmailIds =new HashSet();
            try{
           DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
           DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
           Document doc = dBuilder.parse(in);
           doc.getDocumentElement().normalize();
           NodeList nList = doc.getElementsByTagName("entry");
         
           for (int temp = 0; temp < nList.getLength(); temp++) {
              Node nNode = nList.item(temp);
              if (nNode.getNodeType() == Node.ELEMENT_NODE) {
                 Element eElement = (Element) nNode;
                 if(eElement!=null){
                 Element eEmailId= (Element) eElement.getElementsByTagName("gd:email").item(0);
                 if(eEmailId!=null){
                 gmailIds.add(eEmailId.getAttribute("address"));
                 }
                 }
               }
           }
           request.setAttribute("emailIds",gmailIds);
            }catch (Exception e) {
            e.printStackTrace();
            }
            //CookieConsumer.copyResponse(result, response);
            request.getRequestDispatcher(forwardTo).forward(request, response);
        } catch (Exception e) {
            CookieConsumer.handleException(e, request, response, consumer);
        }
    }
    private static String getTagValue(String sTag, Element eElement){
        NodeList nlList= eElement.getElementsByTagName(sTag).item(0).getChildNodes();
        Node nValue = (Node) nlList.item(0);
        return nValue.getNodeValue();
     }


    private static final long serialVersionUID = 1L;

}