Unexpected visualization

[dancesWithCycles]

Hi folks, I hope this finds you well. Thank you very much for providing this repository. I entered the following instructions in the Bash of my Debian GNU/Linux 10 computer looking for GTFS-Realtime visualization and validation.

git clone https://github.com/OneBusAway/onebusaway-gtfs-realtime-visualizer.git
cd onebusaway-gtfs-realtime-visualizer/
mvn clean install -DskipTests=true
java -jar target/onebusaway-gtfs-realtime-visualizer-0.0.1-SNAPSHOT.jar --vehiclePositionsUrl=dedriver.org/gtfs-rt/vehiclePostions.pb

Here is what I received on the command line:

java -jar target/onebusaway-gtfs-realtime-visualizer-0.0.1-SNAPSHOT.jar --vehiclePositionsUrl=https://dedriver.org/gtfs-rt/vehiclePostions.pb
2021-02-10 10:43:20,973 INFO  [VisualizerService.java:134] : refreshing vehicle positions
2021-02-10 10:43:21,051 INFO  [Server.java:272] : jetty-8.y.z-SNAPSHOT
2021-02-10 10:43:21,265 WARN  [AbstractLifeCycle.java:204] : FAILED [email protected]:8080: java.net.BindException: Address already in use
java.net.BindException: Address already in use
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:461)
	at sun.nio.ch.Net.bind(Net.java:453)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:222)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:85)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:187)
	at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:316)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:265)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.Server.doStart(Server.java:293)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerServer.start(VisualizerServer.java:68)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.onebusaway.guice.jsr250.JSR250Module$ObjectAndMethod.execute(JSR250Module.java:130)
	at org.onebusaway.guice.jsr250.JSR250Module$LifecycleServiceImpl.start(JSR250Module.java:182)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerMain.run(VisualizerMain.java:66)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerMain.main(VisualizerMain.java:39)
2021-02-10 10:43:21,284 WARN  [AbstractLifeCycle.java:204] : FAILED org.eclipse.jetty.server.Server@4f9a3314: java.net.BindException: Address already in use
java.net.BindException: Address already in use
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:461)
	at sun.nio.ch.Net.bind(Net.java:453)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:222)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:85)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:187)
	at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:316)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:265)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.Server.doStart(Server.java:293)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerServer.start(VisualizerServer.java:68)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.onebusaway.guice.jsr250.JSR250Module$ObjectAndMethod.execute(JSR250Module.java:130)
	at org.onebusaway.guice.jsr250.JSR250Module$LifecycleServiceImpl.start(JSR250Module.java:182)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerMain.run(VisualizerMain.java:66)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerMain.main(VisualizerMain.java:39)
2021-02-10 10:43:21,290 WARN  [JSR250Module.java:132] : error invoking @PreDestroy method public void org.onebusaway.gtfs_realtime.visualizer.VisualizerServer.start() throws java.lang.Exception on target org.onebusaway.gtfs_realtime.visualizer.VisualizerServer@3b2c72c2
java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.onebusaway.guice.jsr250.JSR250Module$ObjectAndMethod.execute(JSR250Module.java:130)
	at org.onebusaway.guice.jsr250.JSR250Module$LifecycleServiceImpl.start(JSR250Module.java:182)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerMain.run(VisualizerMain.java:66)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerMain.main(VisualizerMain.java:39)
Caused by: java.net.BindException: Address already in use
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:461)
	at sun.nio.ch.Net.bind(Net.java:453)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:222)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:85)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:187)
	at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:316)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:265)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.Server.doStart(Server.java:293)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.onebusaway.gtfs_realtime.visualizer.VisualizerServer.start(VisualizerServer.java:68)
	... 8 more
2021-02-10 10:43:42,336 INFO  [VisualizerService.java:134] : refreshing vehicle positions
2021-02-10 10:44:02,726 INFO  [VisualizerService.java:134] : refreshing vehicle positions

2021-02-10 10:44:23,074 INFO  [VisualizerService.java:134] : refreshing vehicle positions

Is that something to expect or went something wrong?

Here is my Java and Maven version:

mvn --version
Apache Maven 3.6.0
Maven home: /usr/share/maven
Java version: 1.8.0_282, vendor: AdoptOpenJDK, runtime: /usr/lib/jvm/adoptopenjdk-8-hotspot-amd64/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "4.19.0-11-amd64", arch: "amd64", family: "unix"

I am looking for a way to visualize and validate my GTFS-Realtime feed running at the following address.

https://dedriver.org/gtfs-rt/vehiclePostions.pb