java - What does 4j mean? -

I think many Java libraries use this as a suffix:

  Log4j, couchdb4j, neo4j, launch4j, etc.   
 
 
 Number 4 (for  English )  for  is a name for the promotion, it is being used to indicate that the library is  for Java . 
 
 In. Net, sometimes libraries are prefixed with  n  to indicate that they There are NET versions. For example, Java has to be in Hibernate and NET has EnhiberNet. You also have issues where Java follows this "conference" such as jUnit (where nUnit of .NET). 
 
 As a beginner developer, I was also confused with the 4J naming convention, I thought it was a version indicator, unless I had been taken care of several libraries carrying the suffix. 
 
 Perhaps now a Google search will trigger a meaningful result for "4j" :) 
 
 EDIT: 
 
 I find the original of 4j suffix I'm unable to, but my  best estimate  will be that it has started with log4net, log4php, such as log4cxx