Java can be download  for majority of the platforms on site.

On this site using “source” link from homepage.

Clusterer is free, open source software application licensed via MIT open source license, with additional requirements that any results and derivative work need to cite our application note.

Question 1: How is Clusterer licensed?

Question 2: Where can I download source code?

Question 3: Where do I get Java?

Frequently Asked Questions