To be widely used, a widget should not compel developers to reimplement it every time. That's why widget libraries exist. They provide developers with easily configurable and ready-to-use widgets. In order to promote treemap usage in applications, we have developed a treemap java library : give it tree-structured data set and you will get configurable treemap views, updated when data changes. You could choose the way to compute the drawing or the size of nodes, if you want a classic or squarified treemap, and the size of the nested border if any. The library is implemented in Java, using Swing and design patterns, and is multi-threaded. Finally, it is an open-source project, put on sourceforge (treemap.sourceforge.net), free to be used, distributed and modified.