!! 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]  ==> migrates only java sources (not jsp's)
# allmost all JSP's have to be manually adjusted
# add slf4j-api-1.5.3.jar and slf4j-simple-1.5.3.jar in ./lib
# add the slf4j-api-1.5.3.jar to the eclipse buildpath
# 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 ?)
# a strange log4j config in ProviderConverter:
{{{
        props.setProperty( "log4j.appender.outlog", "org.apache.log4j.ConsoleAppender" );
        props.setProperty( "log4j.appender.outlog.layout", "org.apache.log4j.PatternLayout" );
        props.setProperty( "jspwiki.useLucene", "false" );
        props.setProperty( "log4j.rootCategory", "INFO,outlog" );
}}}
# run the tests and the web-tests
# test with tomcat 
# test with WebSphere (old JSPWiki version and new (slf4j) JSPWiki version


!! Findings

* non-core plugins also need adjustments, an example: 
{{{
SEVERE: Exception starting filter WikiJSPFilter
java.lang.NoClassDefFoundError: org/apache/log4j/Logger
	at org.goodjava.plugin.hitcounter.HitCounter.<clinit>(Unknown Source)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:186)
}}}