I am having problem trying to display a sub category menu using JSTL.

I have a css list menu type for a site I am developing. The name of the menu category is created in a database with a primary key and the submenu also created in a database and has a primary and a (foreign key = "category"). I have managed to retrieve and display this main menu but I don't know how to display the submenu when a user hovers the main menu:

Current code used:

//<div id='cssleftNav'>
<ul>
<c:forEach var = "category" items="${categories.rows}">
<li class='has-sub'>
<a href="category?${category.id}"><span>${category.na me}
</span></a>
<ul>
<c:forEach var = "subcategory" items="${subcategories.rows}">
<li>
<a href="category?${subcategory.id}"><span>${subcateg ory.name}
</span<</a>
</li>
</c:forEach>
</ul>
</li>
</c:forEach>
</cssleftNav
Please Help, i have been at this for a while now