Program: 8594
Project: 8594
Buggy source:
private HSTicketUpdate parseTicketUpdateFromJson(JSONObject updateObject) throws JSONException {
  String updateId=null;
  String userName=null;
  JSONObject byObject=updateObject.getJSONObject("String_Node_Str");
  if (!byObject.isNull("String_Node_Str")) {
    userName=updateObject.getJSONObject("String_Node_Str").getString("String_Node_Str");
  }
  String message=updateObject.getJSONObject("String_Node_Str").getString("String_Node_Str");
  Date update_time=null;
  if (!updateObject.isNull("String_Node_Str")) {
    update_time=parseTime(updateObject.getString("String_Node_Str"));
  }
  JSONArray attachmentObjects=updateObject.getJSONObject("String_Node_Str").getJSONArray("String_Node_Str");
  HSAttachment[] attachments=null;
  if (attachmentObjects != null) {
    int length=attachmentObjects.length();
    ArrayList<HSAttachment> attachmentArray=new ArrayList<HSAttachment>();
    for (int i=0; i < length; i++) {
      JSONObject attachmentData=attachmentObjects.getJSONObject(i);
      String attachment_url=attachmentData.getString("String_Node_Str");
      if (attachment_url.startsWith("String_Node_Str")) {
        attachment_url=instanceUrl.concat(attachment_url.substring(1));
      }
      HSAttachment attachData=HSAttachment.createAttachment(attachment_url,attachmentData.getString("String_Node_Str"),null);
      attachmentArray.add(attachData);
    }
    attachments=attachmentArray.toArray(new HSAttachment[length]);
  }
  if (byObject.getString("String_Node_Str").equals("String_Node_Str")) {
    return HSTicketUpdate.createUpdateByUser(updateId,userName,message,update_time,attachments);
  }
 else {
    return HSTicketUpdate.createUpdateByStaff(updateId,userName,message,update_time,attachments);
  }
}

Fixed version (ground truth):
/** 
 * @param updateObject, can be null if it is private note
 * @return
 * @throws JSONException
 */
private HSTicketUpdate parseTicketUpdateFromJson(JSONObject updateObject) throws JSONException {
  String updateId=null;
  String userName=null;
  if (updateObject.isNull("String_Node_Str")) {
    return null;
  }
  JSONObject messageObject=updateObject.getJSONObject("String_Node_Str");
  if (!messageObject.isNull("String_Node_Str") && messageObject.getString("String_Node_Str").equals("String_Node_Str")) {
    return null;
  }
  JSONObject byObject=updateObject.getJSONObject("String_Node_Str");
  if (!byObject.isNull("String_Node_Str")) {
    userName=updateObject.getJSONObject("String_Node_Str").getString("String_Node_Str");
  }
  String message=updateObject.getJSONObject("String_Node_Str").getString("String_Node_Str");
  Date update_time=null;
  if (!updateObject.isNull("String_Node_Str")) {
    update_time=parseTime(updateObject.getString("String_Node_Str"));
  }
  JSONArray attachmentObjects=updateObject.getJSONObject("String_Node_Str").getJSONArray("String_Node_Str");
  HSAttachment[] attachments=null;
  if (attachmentObjects != null) {
    int length=attachmentObjects.length();
    ArrayList<HSAttachment> attachmentArray=new ArrayList<HSAttachment>();
    for (int i=0; i < length; i++) {
      JSONObject attachmentData=attachmentObjects.getJSONObject(i);
      String attachment_url=attachmentData.getString("String_Node_Str");
      if (attachment_url.startsWith("String_Node_Str")) {
        attachment_url=instanceUrl.concat(attachment_url.substring(1));
      }
      HSAttachment attachData=HSAttachment.createAttachment(attachment_url,attachmentData.getString("String_Node_Str"),null);
      attachmentArray.add(attachData);
    }
    attachments=attachmentArray.toArray(new HSAttachment[length]);
  }
  if (byObject.getString("String_Node_Str").equals("String_Node_Str")) {
    return HSTicketUpdate.createUpdateByUser(updateId,userName,message,update_time,attachments);
  }
 else {
    return HSTicketUpdate.createUpdateByStaff(updateId,userName,message,update_time,attachments);
  }
}