Hi all

i have code use googleseach API

I want to use Thread to improve speed of my program. But i have a problem

here is code

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONObject;

import com.yahoo.search.WebSearchResult;

/**
 * Simple Search using Google ajax Web Services
 * 
 * @author Daniel Jones Copyright 2006 Daniel Jones Licensed under BSD open
 *         source license http://www.opensource.org/licenses/bsd-license.php
 */

public class GoogleSearchEngine extends Thread {



    private String queryString;
    private int maxResult;
    private ArrayList<String> resultGoogleArrayList = null;



    public ArrayList<String> getResultGoogleArrayList() {
        return resultGoogleArrayList;
    }

    public void setResultGoogleArrayList(ArrayList<String> resultGoogleArrayList) {
        this.resultGoogleArrayList = resultGoogleArrayList;
    }

    public String getQueryString() {
        return queryString;
    }

    public void setQueryString(String queryString) {
        this.queryString = queryString;
    }

    public int getMaxResult() {
        return maxResult;
    }

    public void setMaxResult(int maxResult) {
        this.maxResult = maxResult;
    }

    // Put your website here
    public final static String HTTP_REFERER = "http://www.example.com/";

    public static ArrayList<String> makeQuery(String query, int maxResult) {
        ArrayList<String> finalArray = new ArrayList<String>();
        ArrayList<String> returnArray = new ArrayList<String>();
        try {       
            query = URLEncoder.encode(query, "UTF-8");
            int i = 0;
            String line = "";
            StringBuilder builder = new StringBuilder();
            while (true) {

                // Call GoogleAjaxAPI to submit the query
                URL url = new URL("http://ajax.googleapis.com/ajax/services/search/web?start=" + i + "&rsz=large&v=1.0&q=" + query);

                URLConnection connection = url.openConnection();
                if (connection == null) {
                    break;
                }

                // Value i to stop while or Max result
                if (i >= maxResult) {
                    break;
                }

                connection.addRequestProperty("Referer", HTTP_REFERER);

                BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(),"utf-8"));
                while ((line = reader.readLine()) != null) {
                    builder.append(line);
                }

                String response = builder.toString();
                JSONObject json = new JSONObject(response);
                JSONArray ja = json.getJSONObject("responseData").getJSONArray("results");

                for (int j = 0; j < ja.length(); j++) {
                    try {
                        JSONObject k = ja.getJSONObject(j);     
                        // Break string into 2 parts: URL and Title by <br>

                        returnArray.add(k.getString("url") + "<br>" + k.getString("titleNoFormatting"));
                    } 
                    catch (Exception e) {
                        e.printStackTrace();
                    }
                }

                i += 8;
            }

            // Remove objects that is over the max number result required
            if (returnArray.size() > maxResult) {
                for (int k=0; k<maxResult; k++){
                    finalArray.add(returnArray.get(k));
                }
            }
            else 
                return returnArray;

            return finalArray;
        } 
        catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }
    @Override
    public void run() {
        // TODO Auto-generated method stub
        //super.run();
        this.resultGoogleArrayList = GoogleSearchEngine.makeQuery(queryString, maxResult);
        System.out.println("Code run here ");
    }
    public  static void main(String[] args) 
    {
        Thread test = new GoogleSearchEngine(); 
        ((GoogleSearchEngine) test).setQueryString("data ");
        ((GoogleSearchEngine) test).setMaxResult(10);
        test.start();   
        ArrayList<String> returnGoogleArrayList = null;
        returnGoogleArrayList = ((GoogleSearchEngine) test).getResultGoogleArrayList();
         System.out.print("contents of al:" + returnGoogleArrayList);       
    }
}

when i run it, it can run into run method but it don't excute make query methor and return null array.

when i do't use Thread it can nomal .

Can you give me the reason why ? or give a sulution

Thanks