Clojure/Java: Java libraries for spectrum analysis of sound?

This Archived Blog shows a java implementation of the FFT algorithm which is very concise and reads audio files and calculates the frequency spectrum.

You could also check Jtranforms open source FFT library

Unfortunately the blog is gone, here are some other resources on FFT.

• http://web.archive.org/web/20160301081621/http://www.wikijava.org/wiki/The_Fast_Fourier_Transform_in_Java_(part_1)
• http://www.royvanrijn.com/blog/2010/06/creating-shazam-in-java/
• Not java but added for the explanation: https://jakevdp.github.io/blog/2013/08/28/understanding-the-fft/

have a look at the jAudio package in jMir, there is probably much more than what you need ...