title: No Source Code is available for type : GWT Compilation Error
body: <p>I am trying to make get requests by a servlet in my GWT application. On compiling the code I am getting these errors.</p>
  
  <pre><code>[ERROR] Line 16: No source code is available for type org.apache.http.client.ClientProtocolException; did you forget to inherit a required module?
  [ERROR] Line 16: No source code is available for type org.apache.http.ParseException; did you forget to inherit a required module?
  [ERROR] Line 16: No source code is available for type org.json.simple.parser.ParseException; did you forget to inherit a required module?
  </code></pre>
  
  <p>What should I do to remove these errors? 
  Are these classes are not supported by GWT?</p>
  
  <p>Following is the code I am using</p>
  
  <pre><code>public String getJSON() throws ClientProtocolException, IOException, ParseException{
      HttpClient httpclient = new DefaultHttpClient(); 
      JSONParser parser = new JSONParser();
      String url = "some - url - can't disclose";
      HttpResponse response = httpclient.execute(new HttpGet(url));
      JSONObject json_data = (JSONObject)parser.parse(EntityUtils.toString(response.getEntity()));
      JSONArray results = (JSONArray)json_data.get("result");
  }
  </code></pre>
  
  <p>This code is working fine If I use this on a usual java project/ console application.</p>