The JDK path might change when you update JAVA. For Mac you should go to the following path to check the JAVA version installed.
/Library/Java/JavaVirtualMachines/
Next, say JDK version that you find is jdk1.8.0_151.jdk
, the path to home directory within it is the JDK home path.
In my case it was :
/Library/Java/JavaVirtualMachines/jdk1.8.0_151.jdk/Contents/Home
You can configure it by going to File -> Project Structure -> SDKs
.