Login Page Error
<h:outputText value="ENTER USERNAME" ></h:outputText>
<p:inputText value="#{treeBean.username}" id="user"></p:inputText>
<h:outputText value="ENTER PASSWORD" ></h:outputText>
<p:inputText value="#{treeBean.userpass}" id="pass"></p:inputText>
<p:commandButton value="GO"  action="#{treeBean.checkuser}" onclick="redirect()"></p:commandButton>
<script type="text/javascript">
function redirect()
{
window.location="/arcpage/arc.jsf";
}
</script>

public void checkuser()
{
Connection con=null;
try
{
Class.forName("com.mysql.jdbc.Driver");
con=DriverManager.getConnection("jdbc:mysql://localhost:3306/", "root", "root");
try
{
st.executeUpdate("USE ARCPAGE");
String update="SELECT * FROM USER WHERE USER_NAME=? AND USER_PASS=?";
    PreparedStatement prest=con.prepareStatement(update);
    prest.setString(1,username);
    prest.setString(2,userpass);
ResultSet rs=prest.executeQuery();
if(rs.next()==false)
{
check="false";
}
else
{
check="true";
}
    }}}

<script type="text/javascript">
if(check!="true")
{
 window.location="/arcpage/login.jsf";
}
</script>
<Main Page Content>

<p:commandButton value="GO"  action="#{treeBean.checkuser}" />

public String checkuser() {
    User user = userService.find(username, password);

    if (user == null) {
        return "login";
    } else {
        return "arc";
    }
}