The visual nature of geometry makes Java a natural tool for debugging. Rather than drawing by hand the emerging data structures and geometry, an applet that displays the situation would be a wonderful adjunct. Disregarding issues of speed, it is not difficult to create the plumbing necessary to allow a developing applet to run in tandem with a conventional debugger which provides control over the running process. This combination should prove useful to all implementors. Beyond classes and tools that simplify implementation, implementors also need data sets to be used as inputs to algorithms.
Various issues arise here.
First there should be generators for simple data sets that can be used for demonstration. The simplest example is N random points or segments in the plane. These are absolutely necessary for simple debugging of implementations. Finally, there need to be collections of data from real applications. It is unnecessary for each implementor to reinvent input sets.