Just a few typos:
   org.apache.log4j.examples.SortAlgo: [56]
       "interger" should be "integer".

   org.apache.log4j.BasicConfigurator: [96]
   	"isntantiate" should be "instantiate".

   org.apache.log4j.Sort: [20-23]
   	It says "Two example configuration files...", but gives three example 
files (sort1.lcf, sort2.lcf and sort3.lcf).
   	Not only that, you forgot to put "sort4.lcf" in there as well. :)

   org.apache.log4j.PatternLayout: [58-67]
   	Line 61 says "root.warn("Message 2.");", but line 66 says the result of 
this is "WARN  [main]: Message 2" (with no full stop).

   org.apache.log4j.AppenderSkeleton: [22]
        "threashold" should be "threshold" (plus the sentence should end with a 
full stop).

   org.apache.log4j.Priority [51]
        "higlight" should be "highlight".

   org.apache.log4j.performance.NewVsSetLen [100]
        "setLegth" should be "setLength".

   org.apache.log4j.performance.Logging [172]
   	"sleept" should be "sleep".

Also, the format for the "since" tags differs throughout the classes. For 
example:
   "log4j v0.7.0" (in NDC)
   "version 0.8.1" (in PropertyConfigurator)
   "0.8.1" (in BasicConfigurator)

Hardly the most important of issues, but it's just an inconsistency....

BTW, I would've put severity as "trivial", but there's no such entry. :)

Allan.