json parser empty result

Question

I'm new in gwt and new to using Firebug. MY gwt version is 2.0.0. using eclipse and WAMP. my IIS is stoped to run WAMP apache. I run my program on firefox
I have valid json result from tesdb3.php located in "http://localhost/phpmyadmin/tesdb3/datauser.php"

{"item": [{"kode":"002","nama":"bambang gentolet"},
          {"kode":"012","nama":"Algiz"}]}

I add the xml with

<inherits name='com.google.gwt.json.JSON'/>
<inherits name="com.google.gwt.http.HTTP" />

then I try to show it in the gwt with this code.

public class Tesdb3 implements EntryPoint { 

String url= "http://localhost/phpmyadmin/tesdb3/datauser.php";

public void LoadData() throws RequestException{             

    RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, URL.encode(url));

    builder.sendRequest(null, new RequestCallback(){
        @Override
        public void onError(Request request, Throwable exception) {
            Window.alert("error " + exception);
        }
        public void onResponseReceived(Request request,
                Response response) {
              if (200 == response.getStatusCode()) {
                  Window.alert("ok -" + response.getText() + "-" + response.getStatusCode());
              } else {
                  Window.alert("error2 -" + response.getText()+ response.getStatusText() + "-" + response.getStatusCode());
              }         
        }
    });
}

public void onModuleLoad() {        
    try {
        LoadData();
    } catch (RequestException e) {
        e.printStackTrace();
    }       
}
}

I run it in development mode. not hosted mode.
My code didn't show any error. But the result in window alert is "error2 --OK-0".

result Net from firebug is 7 request:
get Tesdb3.html?gwt.codeserv = 200ok
get Tesdb3.css = 200ok
get tesdb3.nocache.js = 200ok
get hosted.html?tesdb3 = aborted
get standard.css = 304 not modified
get hosted.html?tesdb3 = 403 not modified
get datauser.php = 200ok

My question is:

Why the response status code is 0, and the response status text is 'OK'? there was no error in json or Java code.

Why response.getText is empty? Why I can't get any json result even a single character?

Please help me. already 2 months I try to solve this with many source type and I can't get a single result.

This is my datauser.php

  header('Content-type: application/json; charset=UTF-8');
  header('Cache-Control: no-cache');
  header('Pragma: no-cache');

  $link = mysql_connect("localhost", "root", "")
        or die("Could not connect : " . mysql_error());
  mysql_select_db("tesku1") or die("Could not select database" . mysql_error());

  $query = "select * from tabel1";
  $result = mysql_query($query);

  $jumlah_data = mysql_num_rows($result);

  echo '[';

  for ($i=0; $i<=count($result); $i++){
      $row = mysql_fetch_array($result);

      echo '{';
      echo "\"kode\":\"$row[kode]\",";
      echo "\"nama\":\"$row[nama]\"";

      if ($i==count($result)){
       echo '}';
      }else
      echo '},';
  }
  echo ']';

  mysql_free_result($result);

Answer 1

Well, looks like the problem is SOP(Same Origin Policy), and cross site request. From what I get(not detailed though) if the request is cross-site, RequestBuilder can't be used.
For exchange, use getJson() and JSNI overlay types. All example from this tutorial : http://code.google.com/webtoolkit/doc/latest/tutorial/Xsite.html. I change the price value into my database value. At the end..my database showing up in my browser(yeah!yeahhh! (T-T)).