standalone.xml:
<drivers>
<driver name="h2" module="com.h2database.h2">
<xa-datasource-class>org.h2.jdbcx.JdbcDataSource</xa-datasource-class>
</driver>
<driver name="oracle" module="com.oracle.ojdbc6">
<xa-datasource-class>oracle.jdbc.OracleDriver</xa-datasource-class>
</driver>
</drivers>

and in datasource tag:
<datasource jta="true" jndi-name="java:jboss/datasources/Glob01DS" pool-name="Glob01DS" enabled="true" use-java-context="true" use-ccm="true">
<connection-url>jdbc:oracle:thin:....cut</connection-url>
<driver>oracle12</driver>

wont produce any exception even if I am referencing driver which doesn't exist!