The default port chosen by Corda 5 worker crashes the default port that is used by AirPlay on macOS

[dicksonchow]

I have discovered that when I execute the startCorda gradle task on macOS, the Corda log always complains that port 7000 is already in used by some other process.

After some googling, I found that 7000 port is used by AirPlay on macOS by default. In order to run the startCorda task, I have to switch off AirPlay in my system setting to make it works.

I suggest making the listening port number configurable such that we can choose other port number other than port 7000 to avoid the problem.

	at io.javalin.Javalin.start(Javalin.java:184) ~[?:?]
	at io.javalin.Javalin.start(Javalin.java:148) ~[?:?]
	at net.corda.applications.workers.workercommon.internal.WorkerMonitorImpl$startServer$1$1.invoke(WorkerMonitorImpl.kt:114) ~[?:?]
	at net.corda.applications.workers.workercommon.internal.WorkerMonitorImpl$startServer$1$1.invoke(WorkerMonitorImpl.kt:113) ~[?:?]
	at net.corda.utilities.LogUtilsKt.executeWithStdErrSuppressed(LogUtils.kt:46) ~[?:?]
	at net.corda.applications.workers.workercommon.internal.WorkerMonitorImpl$startServer$1.invoke(WorkerMonitorImpl.kt:113) ~[?:?]
	at net.corda.applications.workers.workercommon.internal.WorkerMonitorImpl$startServer$1.invoke(WorkerMonitorImpl.kt:109) ~[?:?]
	at net.corda.utilities.classload.ClassLoadingUtilsKt.executeWithThreadContextClassLoader(ClassLoadingUtils.kt:11) ~[?:?]
	at net.corda.applications.workers.workercommon.internal.WorkerMonitorImpl.startServer(WorkerMonitorImpl.kt:109) ~[?:?]
	at net.corda.applications.workers.workercommon.internal.WorkerMonitorImpl.listen(WorkerMonitorImpl.kt:65) ~[?:?]
	at net.corda.applications.workers.workercommon.WorkerHelpers$Companion.setupMonitor(WorkerHelpers.kt:108) ~[?:?]
	at net.corda.applications.workers.combined.CombinedWorker.startup(CombinedWorker.kt:118) ~[?:?]
	at net.corda.osgi.framework.OSGiFrameworkWrap.startApplication(OSGiFrameworkWrap.java:588) ~[corda-combined-worker-5.0.0.0-Fox1.0.jar:?]
	at net.corda.osgi.framework.OSGiFrameworkMain.main(OSGiFrameworkMain.java:168) ~[corda-combined-worker-5.0.0.0-Fox1.0.jar:?]
Caused by: java.io.IOException: Failed to bind to 0.0.0.0/0.0.0.0:7000
	at org.eclipse.jetty.server.ServerConnector.openAcceptChannel(ServerConnector.java:349) ~[?:?]
	at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:310) ~[?:?]
	at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80) ~[?:?]
	at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:234) ~[?:?]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:73) ~[?:?]
	at org.eclipse.jetty.server.Server.doStart(Server.java:401) ~[?:?]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:73) ~[?:?]
	at io.javalin.jetty.JettyServer.start(JettyServer.kt:65) ~[?:?]
	at io.javalin.Javalin.start(Javalin.java:174) ~[?:?]
	... 13 more
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:552) ~[?:?]
	at sun.nio.ch.ServerSocketChannelImpl.netBind(ServerSocketChannelImpl.java:336) ~[?:?]
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:294) ~[?:?]
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:88) ~[?:?]
	at org.eclipse.jetty.server.ServerConnector.openAcceptChannel(ServerConnector.java:344) ~[?:?]
	at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:310) ~[?:?]
	at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80) ~[?:?]
	at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:234) ~[?:?]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:73) ~[?:?]
	at org.eclipse.jetty.server.Server.doStart(Server.java:401) ~[?:?]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:73) ~[?:?]
	at io.javalin.jetty.JettyServer.start(JettyServer.kt:65) ~[?:?]
	at io.javalin.Javalin.start(Javalin.java:174) ~[?:?]```