Unrecognized VM option 'UseConcMarkSweepGC' when trying to execute main class.

[slackorama]

I'm getting this when I try to exec-main on a simple Java file:

run main: /Users/slackorama/projects/fark/src/main/java/com/slackorama/algs/App.java
Unrecognized VM option 'UseConcMarkSweepGC'
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
fin: /Users/slackorama/projects/fark/src/main/java/com/slackorama/algs/App.java
elapsed: 00:00:00.060

my java version:

openjdk version "15.0.1" 2020-10-20
OpenJDK Runtime Environment (build 15.0.1+9)
OpenJDK 64-Bit Server VM (build 15.0.1+9, mixed mode, sharing)