My code is working properly in Ecclipse but Hackerank gives below error. can anyone explain why?

import java.io.; import java.util.; public class ScannerEx {

public static void main(String[] args) {
    int i = 4;
    double d = 4.0;
    String s = "HackerRank ";

    Scanner scan = new Scanner(System.in);
    /* Declare second integer, double, and String variables. */
    int a;
    double b;
    String c;

/* Read and save an integer, double, and String to your variables.*/
 a=scan.nextInt();
 Scanner scan2=new Scanner(System.in);
 b=scan2.nextDouble();
 Scanner scan3=new Scanner(System.in);
 c=scan3.next();

/* Print the sum of both integer variables on a new line. */
    System.out.println(i+a);
/* Print the sum of the double variables on a new line. */
    System.out.println(d+b);

/* Concatenate and print the String variables on a new line; 
    the 's' variable above should be printed first. */
    System.out.println(s+c);
    scan.close();
}

}