JBoss by default assumes XA drivers and does not support calling multiple non-XA resources within the same transaction. To enable multiple non-XA resources in JBoss, add the property com.arjuna.ats.jta.allowMultipleLastResources to the jbossjta-properties.xml
file, under the <property depends="arjuna" name="jta">
tag:
<property depends="arjuna" name="jta">
<property name="com.arjuna.ats.jta.allowMultipleLastResources" value="true"/>
You may still see warnings in your log file, but ATG applications will run correctly. To suppress these warnings, add the following to your jboss-log4j.xml file:
<category name="com.arjuna.atg.jta.logging">
<priority value="ERROR"/>
</category>
This was the case in ATG 9.3 and I assume still holds true. Another quick reference to the cause is here