Where to add compiler options like -ea in IntelliJ IDEA?

I want to add the -ea option. I set it in Project Settings –> Compiler –> Java Compiler : Additional command line parameters.

But it caused a make error: invalid flag: -ea. P.S.: the above error message may not be the same as yours, because IntelliJ showed error in my native language, not English. I translated it into English.

Answer

The -ea option to enable assertions is passed to the JVM not to the compiler. Add it as a VM option for your runtime configuration.

Specific location in the menu: Run > Edit Configurations… > Configuration > VM options: