File: args
-J-verbose

$ javac @args Main.java

javac neither supports -J options from argfile (no verbose class loading messages printed by the above javac command) nor reports an error.

The -J option could be invalid VM option as well.

File: args
-J-xyz

@javac @args Main.java

Observed: silent compilation
Expected: error message

I verified this with jdk 16 as well as latest local build of "jdk" repo