I can't seem to read the end of the input file, how can i fix this?

This is my code:

import java.io.*;
import java.util.*;

public class revroot
{

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        while (in.hasNextDouble())
        {
            double a = in.nextDouble();
            out.println(Math.sqrt(a));
        }
        out.close();
        }
}


Thanks in advance.