DataTables warning: Requested unknown parameter '4' from the data source for row '' - datatables

Question

Are Days and days that I'm looking for this problem, but nothing resolved it!
This warning appear after the add of a Student to my Database. The persist of the Data is Ok, so i need to hide this error or adjust it.
So i have a Datables that give me this error:
This is my html code:
<script type="text/javascript">
$(document).ready(function () {
$("#companies").dataTable({
"bServerSide": true,
"sAjaxSource": "/studentiSource",
"bProcessing": true,
"sPaginationType": "full_numbers",
"bJQueryUI": true,
"aoColumns": [
{ "sName": "ID", "mDataProp": null,
"bSearchable": false,
"bSortable": false,
"bVisible": false
},
{ "sName": "NOME",},
{ "sName": "COGNOME"},
{ "sName": "USERNAME"},
{ "sName": "PASSWORD" },
{ "fnRender": function (oObj) {
console.log(oObj);
return '<a href=${pageContext.request.contextPath}/modificaStudente.jsp?id=' + oObj.aData[0] + '>' + 'Gestisci' + '</a>';
}}
]
}).makeEditable({
sUpdateURL : "/updateStudenti" ,
sAddURL: "/studenteServlet",
sDeleteURL: "/deleteStudenti",
fnShowError: function (message, action) {
switch (action) {
case "update":
jAlert(message, "Update failed");
break;
case "delete":
jAlert(message, "Delete failed");
break;
case "add":
$("#lblAddError").html(message);
$("#lblAddError").show();
break;
}
},
fnStartProcessingMode: function () {
$("#processing_message").dialog();
},
fnEndProcessingMode: function () {
$("#processing_message").dialog("close");
}
});
});
And the table is:
<div id="container">
<div id="demo_jui">
<button id="btnAddNewRow" value="Ok">Aggiungi nuovo studente...</button>
<button id="btnDeleteRow" value="cancel">Rimuovi utente selezionato</button>
<div id="processing_message" style="display:none" title="Processing">Attendere.. Caricamento dati in corso</div>
<table id="companies" class="display">
<thead>
<tr>
<th>ID</th>
<th>Nome</th>
<th>Cognome</th>
<th>Username</th>
<th>Password</th>
<th>Dispense</th>
</tr>
</thead>
<tbody >
</tbody>
</table>
</div>
<form id="formAddNewRow" action="#" title="Aggiungi nuovo studente">
<label id="lblAddError" style="display:none" class="error"></label>
<input type="hidden" id="id" name="id" value="-1" rel="0" />
<input type="hidden" value="aggiungi" name="action">
<label for="name">Nome</label><input type="text" name="nome" id="name" class="required" rel="1" />
<br />
<label for="name">Cognome</label><input type="text" name="cognome" id="address" rel="2" />
<br />
<label for="name">Username</label><input type="text" name="username" id="postcode"/>
<br />
<label for="name">Password</label><input type="text" name="password" id="town" rel="3"/>
<br />
</form>
</div>
I'm using Datatables 1.9.4

Answer 1

I cant give you a definitive answer, since you did not include the JSON response from the server.
This message usally means that DataTables is looking at your data source for array position 4 (which is the fifth element -- the password field) and not finding it.
You should make sure that you are returning a response with all the fields specified in the datatables definition, including the password field.

Answer 2

The sixth element of your JSON array doesn't contain the value for key '4' because you're fetching a null value, try to parse your JSON array to http://jsoneditoronline.org/ and you'll see it.