JBoss hangs during startup if application calls System.exit() from initialisation code

Issue

JBoss is hanging during startup, and trying to shut it down does not work.

In the thread dump, there is:

"ServerService Thread Pool -- 90" prio=10 tid=0x00007f89f0249000 nid=0x1f52 in Object.wait() [0x00007f89b90fa000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000006d67f6080> (a java.lang.Thread)
    at java.lang.Thread.join(Thread.java:1260)
    - locked <0x00000006d67f6080> (a java.lang.Thread)
    at java.lang.Thread.join(Thread.java:1334)
    at java.lang.ApplicationShutdownHooks.runHooks(ApplicationShutdownHooks.java:106)
    at java.lang.ApplicationShutdownHooks$1.run(ApplicationShutdownHooks.java:46)
    at java.lang.Shutdown.runHooks(Shutdown.java:123)
    at java.lang.Shutdown.sequence(Shutdown.java:167)
    at java.lang.Shutdown.exit(Shutdown.java:212)
    - locked <0x00000006d671a8c8> (a java.lang.Class for java.lang.Shutdown)
    at java.lang.Runtime.exit(Runtime.java:109)
    at java.lang.System.exit(System.java:961)
    at com.liferay.portal.servlet.MainServlet.init(MainServlet.java:222)
    at javax.servlet.GenericServlet.init(GenericServlet.java:242)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1194)
    - locked <0x0000000713e05dc8> (a org.apache.catalina.core.StandardWrapper)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1100)
    - locked <0x0000000713e05dc8> (a org.apache.catalina.core.StandardWrapper)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3591)
    at org.apache.catalina.core.StandardContext.start(StandardContext.java:3798)
    - locked <0x0000000713a093c8> (a org.apache.catalina.core.StandardContext)
    at org.jboss.as.web.deployment.WebDeploymentService.doStart(WebDeploymentService.java:156)
    at org.jboss.as.web.deployment.WebDeploymentService.access$000(WebDeploymentService.java:60)
    at org.jboss.as.web.deployment.WebDeploymentService$1.run(WebDeploymentService.java:93)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:724)