REW and UbuntuStudio - Audio Interface not listed

[marco_76]

Hi,

I was using REW with Debian 10 before without any issues, except that the Waterfall diagram was not working.
Now I switched to UbuntuStudio 20 and installed REW, but my audio interface (Behringer UMC204 is not listed).
I have this Java version installed:

"java -version
openjdk version "1.8.0_265"
OpenJDK Runtime Environment (build 1.8.0_265-8u265-b01-0ubuntu2~20.04-b01)
OpenJDK 64-Bit Server VM (build 25.265-b01, mixed mode)
"
Is this a correct version? REW start and I can analyse data, so this is working.

I'm assuming that the interface is blocked by UbuntuStudio, but I didn't figure out yet by what process.
In Debian it was sufficient to close the browser and to stop jack so that the interface is not used by jack or pulseaudio, but now in Ubuntu Studio it just doesn't come up in the list.

Can anybody help?

 

[marco_76]

I found the problem:

A Java 8 runtime must be installed first using sudo apt-get install openjdk-8-jre or equivalent. Do not install a headless JRE, they lack audio I/O.

I had the headless version installed.