The class org.nineml.coffeesacks.RegisterCoffeeSacks can be passed to the Saxon processor on the command line as the value of the -init option to register the extension functions.

To use this class within your own application code, instantiate the class and pass the underlying configuration to the initialize method:

RegisterCoffeeSacks register = new RegisterCoffeeSacks();
register.initialize(processor.getUnderlyingConfiguration());

This will register the functions with the processor.