[JAVA] Suddenly tomcat run stopped working

environment

Same as the link below

• Prepare the execution environment of Tomcat in IntelliJ Community

Symptoms

Error in gretty's tomcat run task (same for jetty run and app run)

Cannot cast object 'null' with class 'null' to class 'int'. Try 'java.lang.Integer' instead

Cause

Project> build> gretty_ports.properties The contents were empty.

Solution

I deleted the whole file and it passed. When I ran Tomcat Run, it was regenerated with the following contents.

gretty_ports.properties

#Sun Jun 16 12:15:41 JST 2019
statusPort=53051
servicePort=53050

PS

Does the port number look different each time it is regenerated?