Where is the “server log” for Tomcat when running externally from IntelliJ Ultimate?

Question

When running my Vaadin app on Tomcat 8.5 externally from IntelliJ Ultimate 2017.2 on macOS Sierra, I get an error message:

Artifact timepiece-ui:war e

Answer 1

IntelliJ displays Tomcat logs

The accepted Answer by CrazyCoder is correct.

In addition, as commented by Jerry06, IntelliJ Ultimate does automatically display the logs as tabs in the server output pane.

The files backing those logs are stored in the CATALINA_BASE as explained in the other Answer.