Substance is a modern, customizable and high-performing look & feel for Java applications that use the Swing UI toolkit. This look & feel is available for Java 9. Source code can be found at Source Code - https://github.com/kirill-grouchnikov/radiance/tree/master/flamingo
Substance look-and-feel is now part of the Radiance set of libraries. The project is being actively developed on Github. The current pace of the project is to have two releases per year.