public static void main(String[] args) throws Exception {
    final Path path = Paths.get("path", "to", "folder");
    final Path txt = path.resolve("myFile.txt");
    final Path csv = path.resolve("myFile.csv");
    try (
            final Stream<String> lines = Files.lines(txt);
            final PrintWriter pw = new PrintWriter(Files.newBufferedWriter(csv, StandardOpenOption.CREATE_NEW))) {
        lines.map((line) -> line.split("\|")).
                map((line) -> Stream.of(line).collect(Collectors.joining(","))).
                forEach(pw::println);
    }
}

try (
            final Stream<String> lines = Files.lines(txt);
            final PrintWriter pw = new PrintWriter(newBufferedWriter(csv, StandardOpenOption.CREATE_NEW))) {
        lines.map((line) -> line.split("\|")).
                map((line) -> Stream.of(line).collect(joining(","))).
                forEach(pw::println);
    }

public static void main(String[] args) throws Exception {
    final Path path = Paths.get("path", "to", "folder");
    final Path txt = path.resolve("myFile.txt");
    final Path csv = path.resolve("myFile.csv");
    final Charset utf8 = Charset.forName("UTF-8");
    try (
            final Scanner scanner = new Scanner(Files.newBufferedReader(txt, utf8));
            final PrintWriter pw = new PrintWriter(Files.newBufferedWriter(csv, utf8, StandardOpenOption.CREATE_NEW))) {
        while (scanner.hasNextLine()) {
            pw.println(scanner.nextLine().replace('|', ','));
        }
    }
}

try (
            final Scanner scanner = new Scanner(newBufferedReader(txt, utf8));
            final PrintWriter pw = new PrintWriter(newBufferedWriter(csv, utf8, StandardOpenOption.CREATE_NEW))) {
        while (scanner.hasNextLine()) {
            pw.println(scanner.nextLine().replace('|', ','));
        }
    }

public class NewClass {

public static void main(String[] args) throws IOException {

   String data = "one|two|three|four"+"n"+
           "one|two|three|four";
   //Use a BufferedReader to read from actual Text file
    String csv = data.replace("|", ",");
    System.out.println(csv);

    PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("MyCSV.csv")));
    out.println(csv);
    out.close();
}
}

run:
one,two,three,four
one,two,three,four
BUILD SUCCESSFUL (total time: 0 seconds)

public class Test {

    public static void main(String[] args) throws URISyntaxException,
            IOException {

        FileWriter writer = null;
        File file = new File("d:/sample.txt");
        Scanner scan = new Scanner(file);
        File file2 = new File("d:/CSV.csv");
        file.createNewFile();
        writer = new FileWriter(file2);

        while (scan.hasNext()) {
            String csv = scan.nextLine().replace("|", ",");
            System.out.println(csv);
            writer.append(csv);
            writer.append("n");
            writer.flush();
        }
    }
}

He|looked|for|a|book.

  He|picked|up|the|book.