The documentation on how to develop plugins for GrALoG is currently under development. However a good introduction is contained in the java-documentation for the GrALoG-Core-Library, which is available on-line under Java-Doc. It is also recommended to have a look at the GrALoG-examples-plugin, that contains well documented examples to get you started. Both the GrALoG-core-library and the GrALoG-examples-plugin can be downloaded from GrALoG-package-download by selecting gralog-core.zip respectively gralog-examples.zip in the latest release of GrALoG.