Project sdk not defined

Hi,

 I wanted to start trying out closure with cursive and intellij. So installed the ide and the plugin. To open the project I need the add the path to the jdk:

The jdk can be found under:

/usr/lib/jvm/java-9-openjdk-amd64/bin/java

(using a 64 bit xubuntu and openjdk 9) but this path or parts from it are not accepted by the IDE. Does anyone know why?

Thanks alot!