Тестирую - все ок.
package com.javarush.task.task19.task1923;
/*
Слова с цифрами
D:\Programming\1923.txt
D:\Programming\1923-2.txt
*/
import java.io.*;
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new FileReader(args[0]));
BufferedWriter bw = new BufferedWriter(new FileWriter(args[1]));
String line;
while ((line = br.readLine()) != null) {
StringBuilder toFile2 = new StringBuilder();
line = line.replaceAll("\\p{Punct}", "");
String[] words = line.split(" ");
for (int i = 0; i < words.length; i++) {
if (words[i].matches(".*\\d+.*")) {
toFile2.append(words[i] + " ");
}
}
bw.write(toFile2.toString());
}
br.close();
bw.close();
}
}