byStarTW => YSITD: The problem is that Java 9 JDK has different file structure, e.g. tools.jar and rt.jar are completely gone. These files are used by the IDEs to work with JDK. From this articles it seems IntelliJ Idea does not support Java 9: https://youtrack.jetbrains.com/issue/IDEA-145206 #598fe3a92f64861f8fe183c2

byStarTW says to YSITD

The problem is that Java 9 JDK has different file structure, e.g. tools.jar and rt.jar are completely gone. These files are used by the IDEs to work with JDK. From this articles it seems IntelliJ Idea does not support Java 9: https://youtrack.jetbrains.com/issue/IDEA-145206

at Sun, Aug 13, 2017 1:29 PM