To start off, do not use scriptlets in JSP. They are replaced by taglibs and EL since a decade. A commonly used taglib is JSTL which provides the <c:forEach> tag for exact this purpose. With EL you can seamlessly access back end data in JSP pages.

Here's an examlpe how your code is best to be replaced with.

Employee:

public class Employee {
    private Long code;
    private String name;
    // +getters +setters
}

EmployeeServlet:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    List<Employee> employees = employeeDAO.list();
    request.setAttribute("employees", employees);
    request.getRequestDispatcher("employees.jsp").forward(request, response);
}

employees.jsp:

<select name="employee">
    <c:forEach items="${employees}" var="employee">
        <option value="${employee.code}">${employee.name}</option>
    </c:forEach>
</select>

Map the EmployeeServlet on url-pattern of /employees/* and invoke it by http://example.com/contextroot/employees. Good luck and keep your JSP scriptletfree :)

I am a c# coder, but I believe you want something like this:

    <%@ page import="java.util."%>
    <%@ page import="java.lang."%> 
    <%! ArrayList al = c.loadExistingEmpCode(); 

       for(int i=0; i < ai.Count; i++)
       {

    %>

     <option><%= ai[0].toString() %></option>

   <% } %>