Details

Later on we will do something special to convert strings of digits into primitive numeric types. This program does not do that. Here is the program again:

import java.util.Scanner;

class Echo
{
  public static void main (String[] args)
  {
    String inData;
    Scanner scan = new Scanner( System.in );

    System.out.println("Enter the data:");
    inData = scan.nextLine();

    System.out.println("You entered:" + inData );
  }
}

class Echo

The program defines a class named Echo that contains a single method, its main() method.

public static void main ( String[] args )

All main() methods start this way. Every program should have a main() method.

String inData;

The program will create a String object referred to by inData.

Scanner scan = new Scanner( System.in );

This creates a Scanner object, referred to by the identifier scan.

System.out.println("Enter the data:");

This calls the method println to print the characters "Enter the data:" to the monitor.

inData = scan.nextLine();

This uses the nextLine() method of the object referred to by scan to read a line of characters from the keyboard. A String object (referred to by inData) is created to contain the characters.

System.out.println("You entered:" + inData );

This first creates a String by concatenating "You entered:" to characters from inData, then calls println() to print that String to the monitor.