Vector size is zero in jsp though servlet sets it, what is wrong?

Question

servlet sets his attribute
System.out in sevlet shows the values just before thsi command --- request.setAttribute("Names",lvNames);
corresponding JSP code is: The porblem is value of vector size in JSP is zero and tehrfore no loop and no values in combo box...pls help where could be wrong. I am very new to JSPs
<form name="frmAddTx" method="Post" action="MainSrv">
<%
Vector lvNames = new Vector();
%>
table is here
<select name = Name size="1" onChange ="setMsg()">
<% lvNames = (Vector)request.getAttribute("Names");
log("value before any check "+lvNames.size());
if(lvNames.size() != 0)
log("value of "+lvNames.size());
try
for(int i =0;i<lvNames.size();i++)
String temp = (String)lvNames.elementAt(i);
if(lsNewName.equals(temp))
log("selected"+lsNewName);
%>
<option selected"><%=temp%></option>
<%
else
%>
<option><%=temp%></option>
<%
catch(Exception e)
log("error" +e);
%>
</select>

Answer 1

I'm not sure whether the chicken comes before the egg here. Let me see whether I've made an omlette or nuggets:
The JSP displays HTML on the client browser.
There, you have a form named "frmAddTx".
It gets a request from ... somewhere? ... where it gets an array of attributes named "Names" ... from a previous HTML screen? Some HTML form with a "Names" (plural) form element.
Then, when the user submits the form, it calls something called "MainSrv" ... your servlet? ... and passes in the parameter named "Name" (singular).
And then the JSP doesn't have a Vector? HUH??
What am I missing?