Try to add an XA Datasource but don't add any XA properties. You will get the error below on the server.

The problem is that the user doesn't see any error message at all. I assume that this is a known class of problem, but I mention here for bookkeeping purposes.

12:45:43,109 WARN [org.jboss.as.controller] (HttpManagementService-threads - 4) Operation ("add") failed - address: ([
("subsystem" => "datasources"),
("xa-data-source" => "foo")
]): org.jboss.as.controller.OperationFailedException: org.jboss.jca.common.api.validator.ValidateException: IJ010069: Missing required element xa-datasource-property in o
rg.jboss.jca.common.metadata.ds.XADataSourceImpl [ "Failed to create XaDataSource instance for [{
\"operation\" => \"add\",
\"address\" => [
(\"subsystem\" => \"datasources\"),
(\"xa-data-source\" => \"foo\")
],
\"name\" => \"foo\",
\"jndi-name\" => \"bar\",
\"enabled\" => true,
\"driver-name\" => \"h2\",
\"driver-class-name\" => \"org.h2.Driver\",
\"driver-major-version\" => 1,
\"driver-minor-version\" => 2,
\"pool-name\" => \"foo_Pool\",
\"user-name\" => \"asdf\",
\"password\" => \"asdf\",
\"xa-data-source-properties\" => {}
}]
reason:IJ010069: Missing required element xa-datasource-property in org.jboss.jca.common.metadata.ds.XADataSourceImpl" ]
at org.jboss.as.connector.subsystems.datasources.XaDataSourceAdd.startConfigAndAddDependency(XaDataSourceAdd.java:64)
at org.jboss.as.connector.subsystems.datasources.AbstractDataSourceAdd.performRuntime(AbstractDataSourceAdd.java:93)