To install the MockMaker JBuilder plugin, drop mockmaker_jb_plugin.jar in JBuilder's /lib/ext/ directory.
To run MockMaker, select "MockMaker" from the "Tools" menu. This launches a GUI from where you can chose the .class file of the interface that you want to create a Mock implementation for, and the Mock implementation source file to write to.
You are recommended to also read the README for the non-JBuilder integration version of MockMaker. NOTE, however, that the file mockmaker.cfg is included in mockmaker_jb_plugin.jar so cannot be modified so easily.
MockMaker was written by Ivan Moore with contributions from Scott Vlaminck and Henrik Karlsson.