Keyboard Reading Java

To interact with a running program, that is to pass data for computation like user name, password or Employee particulars or Bank account credit and debit operations, two styles exist in a language like Java.

  1. Through Keyboard: It is very common input for practicing a language (but not in realtime). Again two types come here.
    1. Through command-line arguments: Command-line arguments are passed in Java that goes into args string array of main() method.
    2. Through keyboard: Like scanf() in C-lang. Again there are 3 ways in Java using three different classes.
      1. Using
      2. Using
      3. Using java.util.Scanner, mostly used and easier than the above other two. This tutorial illustrates this.
  2. Through GUI: Using text boxes and buttons and followed in realtime.
Following example illustrates Keyboard Reading Java using java,util.Scanner class.
import java.util.Scanner;                
public class StudentInput
 public static void main(String args[])
   Scanner scan1 = new Scanner(;   

   System.out.println("Enter Student Name:");     
   String stdName = scan1.nextLine();

   System.out.println("Enter Circle Radius as a whole number:");
   int radius = scan1.nextInt();

   System.out.println("Enter Recgtangle length, you can enter floating-point value:");
   double length = scan1.nextDouble();

   System.out.println("Enter Recgtangle height, you can enter floating-point value:");
   double height = scan1.nextDouble();
                                                // display the results of computation
   System.out.println("\nStudent Name:" + stdName);
   System.out.println("Circle Perimetetr: " + 2*Math.PI*radius);
   System.out.println("Rectangle Area: " + length*height);

Keyboard Reading JavaOutput Screenshot on Keyboard Reading Java

Scanner scan1 = new Scanner(;

Scanner is from java.util package but not from A Scanner object scan1 is created. The methods of Scanner class nextLine() returns a string, nextInt() returns an integer, nextDouble() returns a double value. Other methods also exist like nextFloat(), nextByte() returning a float and byte.

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