How to create an abstraction library

Actually, there is no such things as an abstraction library in jMax. Every kind of library is built by building a package, and describing its content in the package description file.

The recommended directory structure for a package containing abstraction is:

Of course, as long as the package description file is coherent, you are free to use other directory structures.

Refer to the package documentation for details on how to write the package description file.