I am the creator and maintainer of jDSP - A digital signal processing library for Java. It all started when I was working on some projects and found out that there are no libraries available in Java which can perform complex signal processing, and the few which exist are extremely complicated to use.
I started working on the project in November 2019, and released the first version on Maven in May 2020. This library aims to provide similar functionalities as Python's scipy.signal library so that, a lot of the processing element can be completed on the phone for apps which do not require internet connection. I came across this limitation and realised that this would be of great use.