Selected directory is not a valid home for JDK - Intellij IDEA on Ubuntu
I had the same problem, in my case I wasn't able to select any of the "openjdk" directories under /usr/lib/jvm/, I solved with:
sudo apt-get install openjdk-8-jdk
When restarting intellij it will find the path to the jdk automatically.
For the ones who run into this problem even though you select the right directory under /usr/lib/jvm, there is something you should know : The directories under /usr/lib/jvm are created when your system installs the minimum set of java tools. But it doesn't mean you have the development files available. You need to install the development files :
sudo apt-get install java-1.8.0-openjdk-develAfter installing this package, try to select the directory again and it should work.
Evan Knowles posted a link to https://askubuntu.com/questions/130186/what-is-the-rationale-for-the-usr-directory. It provided me with the solution to the problem.
Instead of using the JDK at /usr/java/jdk1.8.0_25, I instead used the JDK at /usr/local/java/jdk1.8.0_25. The reasons that this works rather than the other are explained in detail within the link.