can i tell the kotlin compiler that it should not allow to use jdk methods that are not in jdk 1.8? (that have a

@since 9

annotation for example). or do i have to use 1.8 to build?

You can point the compiler to the JDK classes to use with the

-jdk-home <path>

parameter. Just using 1.8 is probably the easier way.

good idea, thanks!

you can set

java {
    sourceCompatibility = JavaVersion.VERSION_1_8
    targetCompatibility = JavaVersion.VERSION_1_8
}

that should disallow 9+

i think thats for syntax and not for jdk