I just installed IntelliJ IDEA and when I try to create my first Project it asks for me to set up the Project SDK. When I click on "JDK" it asks for me to select the home directory of the JDK as shown in this image.
I'm having trouble locating where it is.
For a new project select the home directory of the jdk
eg C:\Java\jdk1.7.0_99
or C:\Program Files\Java\jdk1.7.0_99
For an existing project.
1) You need to have a jdk installed on the system.
for instance in
C:\Java\jdk1.7.0_99
2) go to project structure under File menu ctrl+alt+shift+S
3) SDKs is located under Platform Settings. Select it.
4) click the green + up the top of the window.
5) select JDK (I have to use keyboard to select it do not know why).
select the home directory for your jdk installation.
should be good to go.
For IntelliJ IDEA 2017.2 I did the following to fix this issue:
Go to your project structure
Now go to SDKs under platform settings and click the green add button.
Add your JDK path. In my case it was this path C:\Program Files\Java\jdk1.8.0_144
Now Just go Project under Project settings and select the project SDK.
来源：https://stackoverflow.com/questions/16765726/how-to-set-intellij-idea-project-sdk