Starting API ML on Already Used Port Should Give a Specific Message

I attempted to start a newly installed instance of API ML (v2.18) I used these config values:

zowe:
  externalPort: 3000
...
components:
  gateway:
    port: 3000

However, port 3000 was being used by another application on my system and so I received these errors in the job log:

2024-09-04 20:38:01.499 <ZWEAGW1:main:33554513> ZWESVUSR WARN  (o.s.b.w.s.c.AnnotationConfigServletWebServerApplicationContext) Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Failed to start bean 'webServerStartStop'; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat server
2024-09-04 20:38:04.707 <ZWEAGW1:main:33554513> ZWESVUSR WARN  (o.a.c.l.WebappClassLoaderBase) The web application [ROOT] appears to have started a thread named [RxIoScheduler-1 (Evictor)] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:226)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2089)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1104)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:820)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1085)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
 java.lang.Thread.run(Thread.java:825)
2024-09-04 20:38:04.778 <ZWEAGW1:main:33554513> ZWESVUSR ERROR (o.s.b.SpringApplication) Application run failed
org.springframework.context.ApplicationContextException: Failed to start bean 'webServerStartStop'; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat server
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:186)
	at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:58)
	at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:365)
	at java.lang.Iterable.forEach(Iterable.java:86)
	at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:160)
	at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:128)
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:949)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:594)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:732)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:409)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:308)
	at org.zowe.apiml.gateway.GatewayApplication.main(GatewayApplication.java:58)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:90)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:55)
	at java.lang.reflect.Method.invoke(Method.java:508)
	at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:108)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
	at org.springframework.boot.loader.PropertiesLauncher.main(PropertiesLauncher.java:467)
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat server
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebServer.java:229)
	at org.springframework.boot.web.servlet.context.WebServerStartStopLifecycle.start(WebServerStartStopLifecycle.java:43)
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:183)
	... 20 common frames omitted
Caused by: java.lang.IllegalArgumentException: standardService.connector.startFailed
	at org.apache.catalina.core.StandardService.addConnector(StandardService.java:222)
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.addPreviouslyRemovedConnectors(TomcatWebServer.java:282)
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebSe
rver.java:213)
	... 22 common frames omitted
Caused by: org.apache.catalina.LifecycleException: Protocol handler start failed
	at org.apache.catalina.connector.Connector.startInternal(Connector.java:1058)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:164)
	at org.apache.catalina.core.StandardService.addConnector(StandardService.java:219)
	... 24 common frames omitted
Caused by: java.net.SocketException: EDC5111I Permission denied. (errno2=0x744C7246)
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:460)
	at sun.nio.ch.Net.bind(Net.java:452)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:253)
	at org.apache.tomcat.util.net.NioEndpoint.initServerSocket(NioEndpoint.java:268)
	at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:223)
	at org.apache.tomcat.util.net.AbstractEndpoint.bindWithCleanup(AbstractEndpoint.java:1373)
	at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:1459)
	at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:673)
	at org.apache.catalina.connector.Connector.startInternal(Connector.java:1055)
	... 26 common frames omitted

This has messages like Unable to start embedded Tomcat server and EDC5111I Permission denied. but neither of these let me to the conclusion that the port I selected was already in use. Is it possible to detect this situation and issue a specific message when it occurs?

The report names org.zowe.apiml.gateway.GatewayApplication.main and shows Spring Boot/Tomcat startup failures, but no source file or test. Start by tracing gateway startup when port 3000 is occupied and reproduce the failure; done means the job log gives a specific already-in-use-port message, with coverage for that case.