Less is better

Once I got testing working, I turned to log generation. Nothing helps debug more than log files. Apache just put out a release candidate for version 2 of their Log4j utility. I've used version 1 in the past and, of course, "new is always better".

Unlike my experience with v1, I decided to actually learn how the utility is supposed to work, so I could create real log files, and actually manage the output with valid configuration files.  I read the introduction and implementation documentation.  I figured I was ready to try it out.

I downloaded the zip file, unzipped it into my shared library folder.  Created a library in NetBeans included all the jar files, linked them into my project, wrote some test code into my java and ...

Null Test:  Caused an ERROR
org/slf4j/ILoggerFactory
java.lang.NoClassDefFoundError: org/slf4j/ILoggerFactory
 at java.lang.ClassLoader.defineClass1(Native Method)
 at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
 at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
Test org.looman.birddog.data.DataEntityTypeTest FAILED

What!!!  I did everything the way I was told.  Back to the internet for help.  Turns out the documentation for Apache Log4j 2 doesn't include information on implementing the jar files into your classpath.  I guess they assume if you're using it, you must be advanced enough to know how to put jar files into your projects properly.

UGGGHHHHH!!!!!

More internet.  By far the best (and by "best" I means "worst") answer I found was this gem:  "You have to provide one of the various SLF4J implementation .jar files in the classpath, as well as the interface .jar file. This is documented."  by the user EJP

Documented?  Really?  Where?  What implementation .jar files are available?  No links were provided.  That was the whole answer.  And the really surprising thing is this answer got four upvotes!!

Finally, I found this post by SContributor.  The solution is that only two jar files are needed:  log4j-api.2.0-{version}.jar and log4j-core-2.0-{version}.jar.  The {version} may be different, as it refers to the unique version of the jar file.  In my case, I have release candidate 1, so the file names are log4j-api.2.0-rc1.jar and log4j-core-2.0-rc1.jar.  SContributor's solution referenced the Beta 9 version, so the file name was slightly different.  (Log4j is about to move from Release Candidate to General Availability, so your downloaded files might be slightly different).  I removed all the other jar files from the library and lo and behold, it worked beautifully!

Sometimes including everything is not only overkill, but it kills your application altogether.

On a slightly different note:
It took me a bit to get Log4j to find my configuration file.  The solution:  Using the project properties, make sure the folder containing your configuration file is included in the list of source package folders.