UPDATE
I am developing an application and I am making the menu and clicking on the Enter / Register it does not appear the items of dropdown-menu
bootstrap does not work
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet"href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script><scriptsrc="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/bootstrap/bootstrap.min.js"></script>
<script src="js/jquery-1.12.0.min.js" type="text/javascript"></script>
<script src="js/jquery.maskedinput.js" type="text/javascript"></script>
<script src="js/jquery.maskedinput.min.js" type="text/javascript">
</script>
<script src="bootstrap/bootstrap.min.js" type="text/javascript">
</script>
<script src="bootstrap/bootstrap.js" type="text/javascript"></script>
<link rel="stylesheet" href="bootstrap/bootstrap.css">
<link rel="stylesheet" href="css/css.css" type="text/css">
<link rel="stylesheet" href="css/font-awesome.min.css" type="text/css"/>
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css" rel="stylesheet">
<ul class="menu_2">
<div class="btn-group" role="group">
<div class="btn-group" role="group">
<button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Entre/Cadastre-se
<span class="caret"></span>
</button>
<ul class="dropdown-menu">
<li><a href="#"><i class="fa fa-laptop"></i> Meus Pedidos</a></li>
<li><a href="#"><i class="fa fa-gear"></i> Meus Dados</a></li>
<li><a href="#"><i class="fa fa-group"></i> Fale Conosco</li>
<li role="separator" class="divider"></li>
<li><a href="#">Entrar</a></li>
<li><a href="cadastro.jsp"> Cliente novo? Cadastre-se</a></li>
</ul>
</div>
<button type="button" class="carrinho btn btn-default">Carrinho <i class="fa fa-shopping-cart"></i> ( )</button>
</div>
</ul>
.menu_2{
padding: 10px;
font-size: 10pt;
margin-top: 40px;
color: #6495ED;
}
.user{
margin-right: 30px;
font-size: 12pt;
border: 1px solid;
float: left;
height: 49px;
line-height: 49px;
font-family: "Times New Roman";
}