FileMerger.java

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.File;
import java.io.Writer;
import java.io.FileNotFoundException;
import java.io.IOException;

public class FileMerger {
    /* By Chris Clarke, 13.09.2017 */

    public void writeFile(String filename, String text) {
        Writer writer = null;
        try {
            File file = new File(filename);
            writer = new BufferedWriter(new FileWriter(file));
            writer.write(text);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (writer != null) {
                    writer.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public void alternate(String fname, String t1, String t2) {
        String[] text1 = t1.split("\r\n");
        String[] text2 = t2.split("\r\n");
        String result = "";
        for (int i=0;i<text1.length; i++) {
            result += text1[i] + "\r\n";
            if (i<text2.length) result += text2[i]+"\r\n";
        }
        writeFile(fname, result);
    }

    public static void main(String[] args) {
        FileMerger fm = new FileMerger();
        String text1 = "Hello\r\nHow are you?\r\nBye";
        fm.writeFile("File1.dat", text1);
        String text2 = "Welcome to the Computer Lab\r\nThere are 2 Labs in the Senior School";
        fm.writeFile("File2.dat", text2);
        fm.alternate("File3.dat", text1, text2);
    }
}