The Sun/Oracle API, particularly the Javadoc but also the source code itself, provides lots of good examples. You'll use this stuff anyway; when you do, just take a harder look at it than you need to do to get the job done. In particular, JTable is very interesting. It and its associated classes have way too many methods, which muddles it a bit as a learning tool. (I'm becoming convinced that convenience methods are evil.) But note particularly how it uses TableModel. (And also rows, row selection, columns, printing a cell, editing a cell....)
It can take a while to grasp what Sun was doing. OOP tends to be at right angles to everything else; you have to get your brain to think in different ways and then keep it thinking differently.
To try to put OO into two sentences: An object acts as a server, returning information or taking an action upon request. In doing this it can also act as a client and use other servers to do things or return information. (And it can treat, upon request, a client as a server and feed back information on its own schedule and initiative.)