GeoTools 8.4 was very recently released, according to its active blog, and to celebrate here's a starting point for working with GeoTools on the NetBeans Platform:

The sources of the above are below, as a Maven project, so this project can be used in any IDE or command line:

http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.3/tutorials/geospatial/geotools/MyGeospatialSystem

Though quite dated, the GeoTools NetBeans Quick Start is very helpful, especially since it used Maven too, but not the NetBeans Platform, unlike the above sample. From the point of view of NetBeans Platform developers, the GeoTools JMapPane class is very useful, providing the integration point between GeoTools and the rest of the NetBeans Platform application.

Being integrated into the NetBeans Platform means that a host of standard features are now available to the GeoTools features, e.g., print functionality, which only requires a runtime dependency on the NetBeans Print API, together with the "print.printable" client property put into constructor of the TopComponent:

By the way, I've spent some time now and again being confused about the difference between GeoTools and GeoToolkit. Here's an interesting starting point to beginning to understand the differences and history between them. Soon I'd like to have an example similar for the above for GeoToolkit.