retrieving data from 2 table based on given empid in (oracle) javaservlet

retrieving data from 2 table based on given empid in (oracle) javaservlet

am trying to retrieve a data from 2 table then it is not possible to
retrieved.my main intence is for a given id number dis is not possible.am
entered a empid that id is not going interact with the query if i give the
id directly in query this will be executed. my code is int s1 =
Integer.parseInt(req.getParameter("empid"));
pstmt.setInt(1,s1);
pstmt=con.prepareStatement("SELECT * FROM saldetails Natural Join
empdetails where empid=s1");
pstmt.executeUpdate();
rs = pstmt.executeQuery() ;
...................please help me(servlets)