This is a short summary which describes how to add much more logging to Openfire. This will also work with Smack and Spark and ever other java application, it's described in detail here: http://slf4j.org/extensions.html#javaagent
Get javassist.jar and slf4j-ext-1.6.4.jar (at least slf4j-ext-1.6.0.jar) and put the files in a directory.
http://www.csg.ci.i.u-tokyo.ac.jp/~chiba/javassist/ - 3.16.0-GA
http://slf4j.org/download.html - slf4j-1.6.4.zip
Add to the java start command:
-javaagent:/path-to/slf4j-ext-1.6.4.jar=time,verbose,level=debug,ignore=org/slf4 j/:ch/qos/:org/apache/:org/dom4j/:java/util/:com/sun/:org/xml/:sun/:org/hsqldb/: org/postgresql/:org/logicalcobwebs/:java/sql/:\$java/:org/jaxen/:org/xmlpull/:or g/xmpp/:com/googlecode/:gnu/inet/:org/eclipse/:org/jivesoftware/openfire/plugin/ :org/bouncycastle/:javax/servlet/:com/opensymphony/:uk/ltd/:org/jrobin/:org/jive software/openfire/fastpath/:org/jivesoftware/xmpp/:org/jivesoftware/openfire/sip /:org/jivesoftware/openfire/archive/:org/jinglenodes/:redstone/:net/sf/kraken/:o rg/jivesoftware/openfire/reporting/:org/picocontainer/
Then Openfire should start fine without exceptions. "-Xverify:none" is not needed as far as I can tell.
Other Openfire classes which one may want to ignore, depending on the interest.
If log4j.xml can not be found and nothing is logged then add its path to the classpath.