SVN or Subversion is one of the popular source control systems used in the Java world for source code management. There are a lot of source control systems available e.g. Git, Perforce, CVS, ClearCase, VSS, but SVN has its own place among Java developer and open source communities. Knowledge of source control systems is a must for any professional programmer. New users of subversion are often confused between three things trunk, tags, and branches. Questions like, what is the difference between a tag and a branch in subversion is frequently asked in various Java forums and chat rooms.