In an earlier jAlbum 20 beta I was actually loading the file metadata and updating the UI components from the AWT thread, but this was slow as it only utilized one CPU core. Furthermore this made scrolling feel sluggish. I then fixed this to use multiple background threads for reading metadata, but forgot to ensure that they passed the result over to the AWT thread when finally updating the comment text field component for instance.
During the last couple of years cpus exhibited stalling single thread rating. So I am happy with jAlbum making efficient use of all cores available.
The number of cores (AMD Ryzen™ 9 3950X: 16 cores, 32 threads) has grown dramatically. My i7-6700K, 5 years old, 4 cores, 8 threads, still exhibits excellent performance when running jAlbum. Multithreading really matters.
BTW: systemd parallelizes Linux system boot using the make paradigm of dependencies, which results in nice graphs: http://mistelberger.net/boot.svg Heated discussions are warranted.