Combo box+jsp+servlet

[Lain0x]

Código:

<select name="sel" style="width: 246px" ><option value="">Select</option>
<% 


    
     String prod[] = new String[6]; 
    
       prod =  (String[]) request.getSession().getAttribute("departamento");
    
          
     


           for(int i=0;i<6;i++){ 
               if(prod[i]!=null){
                %>
           
          <option value="prod[i]"><%=prod[i]%></option><% 
   }
                             }
       %>   
</select><tr>

Código:

       <%
        String[] option=request.getParameterValues("sel");
       
 
             for (int n = 0; n < option.length; n++) {
%>
 <%= option[n] %> <br>
 
 <%
  }
                        
%>

Me muestra null ( java.lang.NullPointerException)