The kallasoft SmugMug Java API is licensed under the Apache License v2.0. A copy of the license is available inside the Complete download in the /docs subdirectory or you can download a copy of it here.
The long and short of the API being under the Apache License v2.0 is that you are free to use the API in an open source or commercial product, but you need to provide full credits to the kallasoft SmugMug Java API in the documentation of your product somewhere.
For a complete reference, the Apache License v2.0 FAQ is an excellent resource. A summary of the requirements are below for reference:
It allows you to:
- freely download and use Apache software, in whole or in part, for personal, company internal, or commercial purposes;
- use Apache software in packages or distributions that you create.
It forbids you to:
- redistribute any piece of Apache-originated software without proper attribution;
- use any marks owned by The Apache Software Foundation in any way that might state or imply that the Foundation endorses your distribution;
- use any marks owned by The Apache Software Foundation in any way that might state or imply that you created the Apache software in question.
It requires you to:
- include a copy of the license in any redistribution you may make that includes Apache software;
- provide clear attribution to The Apache Software Foundation for any distributions that include Apache software.
It does not require you to:
- include the source of the Apache software itself, or of any modifications you may have made to it, in any redistribution you may assemble that includes it;
- submit changes that you make to the software back to the Apache Software Foundation (though such feedback is encouraged).