I am using Intellij IDEA 2017.2.5 on Linux Mint 18.2 and trying to add new openjdk-9 SDK but IDEA does not accept openjdk
“ Ubuntu PPA for OpenJDK” currently has very old build of openjdk-9(9~b115-1ubuntu1).
So the IDEA does not recognize it as a valid SDK.
I removed current installed version:
sudo apt-get remove '^openjdk-9.*'
Then I have downloaded newer .deb build(9~b181) files including jre,jre-headless,... from launchpad build archive.
sudo dpkg -i openjdk-9-jre-headless_9_b181-4_amd64.deb
openjdk-9-jre_9_b181-4_amd64.deb
openjdk-9-jdk-headless_9_b181-4_amd64.deb
openjdk-9-jdk_9_b181-4_amd64.deb
Just Execute the above command at a single line, line breaks are for better readability.
Ignore any error complaining about:
"Package libpng16-16 is not installed."
Next execute the following:
sudo apt-get install -f
Now after installing this build of openjdk-9 the IDEA is happy with SDK home.
Thanks @y.bedrov for his useful comment.
Update: However this solution enables you to declare openjdk-9 in the mentioned IDEA version(2017-2) but you are not able to compile any class within the IDEA itself. You can only compile your application with elder jdk and run it with openjdk-9. There is an other issue which indicates this here.
In the newer IDEA versions(I have tested 2017.3) this build of openjdk is not allowed to be used as new SDK any more, see this issue.
The short reason is an issue in Debian package which contains incorrectly compiled lib/jrt-fs.jar file.
See this Answer for more information