Best way to store the company-Brands list ?

Question

I am going to use a Java object in my Jsp. My Jsp has 2 dropdowns as follows. One is Company dropdown and second is corresponding brand dropdown.
Each Company owns bunch of brands as follows:
Coca ----- Classis
Diet
Lemon
GM ---------Chevrolet
Corvette
Saba
Gap---------Trouser
Shirts
Jackets
So, now you know. In my Jsp will be first dropdown which will have 3 Company names to select and the second dropdown will immediately show the bunch of corresponding brands, depending upon what company User selects in first dropdown.
Two questions:
I get companies and brands from database. Now I want to populate the object with all above info and send it to Jsp page for both the dropdowns to get populated as I mentioned above. I will be using the taglibs in jsp page like c:forEach and c:value c:out etc
a>What is the best way that i can store this company-brand info on server side and push it to Jsp page ? Should I go collections/ ArrayList OR SET OR what is best ?
If you have sample code for storing it will be helpful
b>I want to know how this object in a> I can loopover and show the company , brand values in my Jsp page dropdown using taglibs.
code snippet will surely help me. bcoz I want to store these values in an javascript array and each time user selects different brand it should fire a call to javascript function which would basically populate appropriate brand list in second SELECt dropdown. So more call to server for different company selection.
thanks again.
pp

Answer 1

I would use a Map<String, Set> or Map<String, List> (using Java 5 generics notation here to show clearly what is in the map, but using generics is not required).
The keys in the map are the company names, the values are Sets or Lists of brand names.
This snippet will get keys and values from a Map called companyBrandsMap:<c:forEach var="mapElement" items="${companyBrandsMap}">
   Company: <c:out value="${mapElement.key}"/><br>
   Brands:<c:forEach var="listElement" items="${mapElement.value}">
     <c:out value="${listElement}"/><br>
   </c:forEach><br>
</c:forEach>This code just prints the values, you can put your JavaScript code around that.