Tools.java

import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Tools {
    public void combineFiles(File fileInput, File fileOutput) throws IOException {
        BufferedWriter writer = new BufferedWriter(new FileWriter(fileOutput));
        BufferedReader reader = new BufferedReader(new FileReader(fileInput));

        String line;

        while ((line = reader.readLine()) != null) {
            writer.write(line + "\n");
        }

        writer.close();
        reader.close();
    }

    public int findNumberFromString(String str) {
        Pattern p = Pattern.compile("\\d+"); // Defines a pattern to search a string for only numbers.
        Matcher m = p.matcher(str); // Find the numbers in a given string using the searching pattern.
        if(m.find()) {
            return Integer.parseInt(m.group());
        }

        return Integer.MIN_VALUE;
    }
}