SUMMARY
When initially installing Wildfly 11.0.0 Final, the installation comes pre-configured with a datasource labeled "Example DS".
When this datasource is deleted, some configuration for it remains in the standalone.xml file for the standalone server mode.
WORKAROUND
Removing this configuration manually and restarting Wildfly in standalone mode resolves the issue. (I tested by searching for "ExampleDS" as a string match in vi and deleting the one line the match found)
BUG JUSTIFICATION
- I would expect anything labeled as "Example" to be deleted by an administrator in most environments
- I would expect deleted items to be fully removed upon deletion so remnant configuration couldn't cause issues with unrelated deployments (i.e. deployments which don't specifically require the deleted item)