JHylaFAX uses a couple of 3rd party libraries.
The gnu.hylafax library was modified slightly to accomodate JHylaFAX's requirements. A patch is available here (see patches directory for older patches).
The easiest way to build JHylaFAX is using Apache Maven 1.x:
Extract the JHylaFAX source archive and change to the project directory (the top level directory that contains the file project.xml).
Build a Jar
To build a jar that includes all dependencies, run:
maven javaapp:jar
Create Eclipse Project
To create Eclipse project files, run:
maven eclipse
Then select File->Import->Existing Projects into Workspace and choose the project directory.