2018.4.12 The latest stable version of NetBeans 8.2 at the time of writing does not support JDK 9 and will not work properly. Although it starts, nothing is displayed when the project is opened, so it is useless.
By using the Nightly version, it will work in the JDK9 environment for the time being, but I do not recommend it because it has a bad reputation on StackOverFlow. Nightly version download link
You can check if there is a 1.8.x directory here If it is not included, please download it from the link below. http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
There is no problem if you edit the environment variable
JAVA_HOME to make JDK8 the main.
JAVA_HOME settings on Mac
If you want to use JDK8 only with NetBeans, please set as follows.
Uncomment the commented out and specify the path of
Contents / Home of your JDK8 directory.
Now it works.