I can't find the terminal where the message is supposed to show. How is it called? I'm guessing it should be in View->Tool Windows but nothing from there seems to work. It's a Maven project and all I can see is GlassFish log.
System.out and System.err output is written to either the Run or the Debug tool window depending on whether you launch the run/debug configuration as Run or Debug. See https://www.jetbrains.com/idea/help/running-and-debugging.html and https://www.jetbrains.com/idea/help/run-tool-window.html for more information (Same information is in the Help guide of the IntelliJ IDEA Ultimate version).
In Java EE applications with Tomcat container, if you want to see the result of prints like System.out.println(), first go to Run > Edit Configurations and select your tomcat server in the left menu, then open Logs tab and check 'Show console when a message is printed to standard output stream'
Click on the below image to figure out.
For running mode:
View -> Tool Windows -> Run
For debugging mode:
View -> Tool Windows -> Debug
You must be on one of the above two states in order to accomplish this action.
来源：https://stackoverflow.com/questions/31656596/system-out-println-where-does-it-write-to-in-intellij-idea