Jasperreport outputs quiet a bit of debug messages when generating print objects. To get rid of them, edit the log4j.xml file in your jboss/server/default/conf directory and add the following lines in the Limit Categories section of the file.
<!-- Limit the net.sf.jasperreports to WARN since logging to DEBUG floods your log with unnecessary messages -->
<category name="net.sf.jasperreports">
<priority value="WARN"/>
</category>