Virtual Java Operating Tool
It is difficult for the users to remember different commands available in various operating system shells. Thus, the authors' paper is to allow the users of various OS to use the same set of commands provided by their shell on any of the operating systems i.e. they have to build such a Shell system which has a similar behavior over different operating systems such as DOS, Windows and Linux. Their problem was providing platform independence to their shell. So in order to overcome this problem they chose to use JAVA.