Blackboard has a tag library which allows you to put familar Blackboard looking html objects into your Building block. One element in the tag library is an inventoryList, which gives you a nice looking list of items. An inventory list in Blackboard might render something like this:

The code to generate this list can be seen below. One special functionality of this list is to be able to re-order your list. This is done by sending an ajax call to your reorderingUrl anytime an item is moved. However, I noticed that my objects were not given the correct Id. Makes it difficult to reorder an item when your passing out incorrect Ids. 

Notice the itemIdAccessor="getId()" this means that item.getId() should be called to get the Id for the item. After some digging I found that getId() must return a String (it was an Integer in my case) to work correctly. This bugged me though since most Ids are typically not Strings. Oh well.