To reproduce

#1 do a hot-deploy
#2 do a hot-undeploy
#3 use jconsole to check the installed services. you should see jboss.deployment.yourdeployment

As a result redeploy fails with

Caused by: org.jboss.as.server.deployment.DeploymentUnitProcessingException: Failed to mount deployment content
at org.jboss.as.server.deployment.module.DeploymentRootMountProcessor.deploy(DeploymentRootMountProcessor.java:69)
at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:85)
... 4 more
Caused by: java.io.IOException: Filsystem already mounted at mount point ""/content/example-simple.jar""
at org.jboss.vfs.VFS.mount(VFS.java:159)
at org.jboss.vfs.VFS.doMount(VFS.java:379)
at org.jboss.vfs.VFS.mountZip(VFS.java:405)
at org.jboss.as.server.deployment.impl.ServerDeploymentRepositoryImpl.mountDeploymentContent(ServerDeploymentRepositoryImpl.java:78)
at org.jboss.as.server.deployment.module.DeploymentRootMountProcessor.deploy(DeploymentRootMountProcessor.java:65)