On my Mac 10.11.3 I've installed the Eclipse JEE IDE (Version: Neon.3
Release (4.6.3))
I also installed apache-tomcat 9 on my Mac, using the following commands :

sudo mkdir -p /usr/local
sudo mv ~/Downloads/apache-tomcat-9.0.0.M21 /usr/local
sudo rm-f /Library/Tomcat
sudo ln -s /usr/local/apache-tomcat-9.0.0.M21/ /Library/Tomcat
sudo chown -R roparzhhemon /Library/Tomcat
sudo chmod +x /Library/Tomcat/bin/*.sh

When I try "Run as server" on a minimal html file in JEE, I get the following
error message :

Could not load the Tomcat server configuration at /Servers/Tomcat v9.0 Sever
at localhost-config. The configuration may be corrupt or incomplete.

Any help appreciated.