When removing a datasource, sporadically this exception appears in the log:
12:49:58,224 WARN [org.jboss.msc.service.fail] (MSC service thread 1-8) MSC000004: Failure during stop of service org.wildfly.data-source.ds51: java.lang.NullPointerException at org.jboss.as.connector.subsystems.datasources.AbstractDataSourceService.stop(AbstractDataSourceService.java:161) at org.jboss.msc.service.ServiceControllerImpl$StopTask.stopService(ServiceControllerImpl.java:2056) at org.jboss.msc.service.ServiceControllerImpl$StopTask.run(ServiceControllerImpl.java:2017) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)
This doesn't seem to happen on WildFly 9.x, only on recent master.
I suspect that this could lead to some resource leaks, but didn't study it further.