Problema ao colocar datepicker em um input

failed to load resource the server responded with a status of 404 (not found)

<link type="text/css" href="css/jquery-ui.css" rel="stylesheet"/> <script type="text/javascript" src="js/jquery.js"></script> <script type="text/javascript" src="js/jquery-ui.js"></script>

<script type="text/javascript"> $("#dataFinalizacao").datepicker({dateFormat: 'dd/mm/yy',changeMonth: true,changeYear: true}); </script>

<input type="text" id="dataFinalizacao" name="dataFinalizacao" value="<fmt:formatDate value="${tarefa.dataFinalizacao.time}" pattern="dd/MM/yyyy"/>"/>