Problem Building Aggregate - 'Address already in use' when starting server

I'm trying to install Aggregate on a Raspberry Pi 4 (with 4 GB of RAM).
I've installed Tomcat - and it successfully delivers the test page.
I've installed Postgresql - and run the initialisation commands.
I've had some trouble getting gradlew runAppWar to compile. But I've settled on Java 8 and Gradle 4.5.1 - and it appears to run almost to the end when it comes up with an error 'Error starting server' as the Address is already in use.
If I use netsat I can see that port 8080 is already in use - which is Tomcat.
Any suggestions as to how to overcome this welcomed!


sudo netstat -nap | grep 8080
tcp6 0 0 :::8080 :::* LISTEN 468/java

16:07:26 ERROR Error starting server Address already in use
at Method) ~[na:1.8.0_212]
at ~[na:1.8.0_212]
at ~[na:1.8.0_212

16:07:26 INFO default runs at:
16:07:26 INFO http://localhost:8080/
:appRunWar FAILED
FAILURE: Build failed with an exception.