Workbench throwing java.net.BindException: Address already in use exception

Problem

Workbench is not able to start, and java.net.BindException is found in mci.log

java.lang.RuntimeException: java.io.IOException: Failed to bind to 0.0.0.0/0.0.0.0:8080
	at org.eclipse.jetty.setuid.SetUIDListener.lifeCycleStarting(SetUIDListener.java:229)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.setStarting(AbstractLifeCycle.java:205)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72)
	at com.datamigrators.mettle.setup.SetupServerCommand$SetupImpl.run(SetupServerCommand.java:175)
	at com.datamigrators.mettle.setup.SetupServerCommand.run(SetupServerCommand.java:99)
	at com.datamigrators.mettle.setup.SetupServerCommand.run(SetupServerCommand.java:71)
	at com.datamigrators.mettle.setup.StartServerCommand.run(StartServerCommand.java:35)
	at io.dropwizard.cli.Cli.run(Cli.java:78)
	at io.dropwizard.Application.run(Application.java:94)
	at com.datamigrators.mettle.MettleApplication.main(MettleApplication.java:69)
Caused by: java.io.IOException: Failed to bind to 0.0.0.0/0.0.0.0:8080
	at org.eclipse.jetty.server.ServerConnector.openAcceptChannel(ServerConnector.java:349)
	at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:310)
	at org.eclipse.jetty.setuid.SetUIDListener.lifeCycleStarting(SetUIDListener.java:216)
	... 9 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: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.ServerConnector.openAcceptChannel(ServerConnector.java:344)
	... 11 more

Cause

The default port of workbench is 8080/8081, when a conflict in port is found, the java.net.BindException will be thrown

Resolution

Identify the ports used, and look for other processes that are using the same port with netstat

sudo netstat -plten | grep 8080

(the sudo may or may not be required depending on whether your ID can run netstat)

This will return results like

tcp6       0      0 :::8080                 :::*                    LISTEN      0          31457      1396/java

You can find out which process is using the same port by searching the running processes via ps

ps -ef | grep 1396

You can either change the port of the conflicted process or change the ports of workbench to resolve the java.net.BindException

To change the port of Workbench, refer to https://datamigrators.atlassian.net/wiki/spaces/MCIDOC/pages/588972035/Configuring+MettleCI+Workbench+to+use+a+Custom+Port+Number?src=search