!! SLF4J , Simple Logging Facade for Java

[website|http://www.slf4j.org/]
[JIRA issue 376|https://issues.apache.org/jira/browse/JSPWIKI-376]

!! Steps
# run the [slf4j migrator|http://www.slf4j.org/migrator.html]
# add the slf4j-api.jar to the eclipse buildpath
# add the slf4j-simple-1.5.3.jar in tests/lib
# src change: ''log.fatal('' ==> ''log.error(''
# src change: slf4j log methods only accept Strings, so ''log.error(Exception)'' ==> ''log.error(Exception.toString())''
# PropertyConfigurator.configure(props) all over the place (mostly in tests) ==> move log4j properties from jspwiki.properties to separate log4j.properties (in classpath) ?
# NDC => MDC ?, these are only in the two ServletFilters, if we still need them, what will we use as key (cookie ?)
# change build.xml so that slf4j-api.jar is added to WEB-INF/lib
# run the tests and the web-tests
# test with tomcat 
# test with WebSphere (old JSPWiki version and new (slf4j) JSPWiki version