я придумал такое решение. вроде логически правильное?
package com.javarush.task.task18.task1820;
/*
Округление чисел
*/
import java.io.*;
import java.text.*;
import java.util.ArrayList;
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String name1 = reader.readLine();
String name2 = reader.readLine();
BufferedReader reader1 = new BufferedReader(new FileReader(name1));
BufferedWriter writer = new BufferedWriter(new FileWriter(name2));
DecimalFormat df = new DecimalFormat("#");
ArrayList<Double> ar = new ArrayList<>();
String s = null;
double d = 0;
while (reader1.readLine() != null) {
s = reader1.readLine().replace(' ', '.');
ar.add(Double.parseDouble(s));
}
for (double dd : ar) {
long l= Math.round(dd);
s=s.valueOf(l);
writer.write(s);
}
reader.close();
reader1.close();
writer.close();
}
}