Take a peek at the jAlbum API (Javadoc format) to discover all the goodies that are provided freely to application developers. Here's an overview of some classes that can be reused:
Multiple string search and replace utility. This class accepts any number of search+replace string pairs to be added. It can then operate on either an input String or stream and replace all occurances of any search pattern with its corresponding replace string.
A utility class that contain various IO related methods (read text file, copy file etc). It can be used to simplify advanced scripting in jAlbum skins.
Flexible, yet very easy to use layout manager that the jAlbum application makes heavy use of. RiverLayout is inspired by the way HTML formats text. RiverLayout is similar to FlowLayout in the sense that the UI components flow, usually from left to right, as they are added to a container, but control strings like "br", "tab" and "p" can be used to better adjust the location. The "tab" string for instance greatly simplifies the construction of forms.
For more info see the RiverLayout project page.