What Method is used to read user inputs from standard input device in java?

Answer 1

In Java, System.in refers to the standard input stream (stdin). System.in is an instance of InputStream, which has a basic read method that allows you to read in one byte of data at a time.

Quick example:

System.out.println(System.in.read()); //User inputs "A", output is 65

Because the functionality of InputStream is so limited, Java offers more complex classes that can deal with input. Scanner is often used, which allows you to easily iterate through numerical input, entire lines of input, and user defined patterns.

Another example with Scanner:

Scanner sc = new Scanner(System.in);

System.out.println(sc.nextLine()); //User inputs "Hello World", output is "Hello World"

Scanner has many other methods that are best left to a separate question. It is worth noting that when you interact with System.in you need to handle possible IOExceptions.