You can place the *-service.xml file definining the MBean, in the .war/META-INF/ folder.
What about <module> entry from ear/META-INF/jboss-app.xml. Where would it go in case of WAR deployment (no EAR/META-INF directory)?
You don't need that entry.
It works fine if I put jboss-sevice.xml into war/META-INF: Mbean gets started. But if I rename jboss-sevice.xml to say mysrv-sevice.xml - it is ignored. Is it working as expected? Should I put all MBean definitions into jboss-sevice.xml?
The jboss-sevice.xml content:
<mbean name="wa:name=MySrv" code="wa.MySrv"/>
Ah right! It has to be jboss-service.xml. We only look for this specific file.