System.in in java means to take input from the keyboard or user. System. out in java means to print the output to console.Click to see full answer. Also asked, what is system in in Java?System.in is an InputStream which is typically connected to keyboard input of console programs. System.in is not used as often since data is commonly passed to a command line Java application via command line arguments, or configuration files. This is a separate input mechanism from Java IO.One may also ask, what is the purpose of the system class in Java? The purpose of the System class is to provide access to system resources. It contains accessibility to standard input, standart output, error output streams, current time in millis, terminating the application, etc. Keeping this in view, what is scanner system in in Java? Scanner: The Scanner class is a class in java.util, which allows the user to read values of various types. System.in: An InputStream which is typically connected to keyboard input of console programs. Scanner S=new Scanner(System.in)What is a system class?System class in java is a predefined class which contains method like println,in etc. You might have observed that we write System.out.println(“hello world”) here System is the class name, out is the inner class which contains definition for the print method.