As per the 4.2 change log (http://jira.jboss.com/jira/secure/ConfigureReport.jspa?versions=12311408&versions=12311037&versions=12310819§ions=.184.108.40.206.220.127.116.11.5&style=none&selectedProjectId=10030&reportKey=pl.net.mamut%3Areleasenotes&Next=Next) and these 2 JIRA issues
this seems to be the first step towards allowing applications to have their own log4j.properties bundled as part of their application packaging.
1. Should my application start using jboss-log4j.xml like it use to use log4j.xml
Going by the JIRA issues that i posted above, yes you can start using the jboss-log4j.xml like you used the log4j.xml in the earlier versions.