Тестил по разному
package com.javarush.task.task19.task1925;
/*
Длинные слова
*/
import java.io.*;
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new FileReader(args[0]));
BufferedWriter writer = new BufferedWriter(new FileWriter(args[1]));
String b = null;
int count = 0;
int count1 = 0;
String c = null;
while (reader.ready()){
if (count1<1){
c= reader.readLine()+" ";
count1++;}
else c+=reader.readLine() + " ";
}
reader.close();
System.out.println(c);
String[] a = c.split(" ");
for (int i = 0; i <a.length ; i++) {
if (a[i].length()>6)
if (i==0&& count<1){
b = a[i]+",";
count++;}
else b+=a[i]+",";}
b=b.substring(0,b.length()-1);
writer.write(b);
writer.flush();
writer.close();
}
}