Old Java vs Java 8 - read file and keep unique words

data.txt

aaa ccc
ddd
bbb
aaa bbb ccc ddd
bbb ddd
aaa bbb

Java8UniqueWords.java

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Scanner;
import java.util.stream.Stream;

import static java.util.stream.Collectors.joining;

/**
 * @author Lee, SeongHyun (Kevin)
 * @since 2015-04-01
 */
public class Java8UniqueWords {
  public static void main(String[] args) throws IOException {

    System.out.print("Enter filename: ");
    try (final Stream<String> lines = Files.lines(Paths.get(new Scanner(System.in).nextLine()))
                                           .map(line -> line.split("[\\s]+"))
                                           .flatMap(Arrays::stream)
                                           .distinct()
                                           .sorted()) {
      final String uniqueWords = lines.collect(joining(", "));
      System.out.println(uniqueWords);
    }

  }
}

OldJavaUniqueWords.java

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

/**
 * @author Lee, SeongHyun (Kevin)
 * @since 2015-04-01
 */
public class OldJavaUniqueWords {
  public static void main(String[] args) throws IOException {

    System.out.print("Enter filename: ");
    String filename = new Scanner(System.in).nextLine();
    List<String> uniqueWords = new ArrayList<>();
    try (FileReader fileReader = new FileReader(new File(filename));
         BufferedReader reader = new BufferedReader(fileReader)) {
      String line = reader.readLine();
      while (line != null) {
        String[] words = line.split("[\\s]+");
        for (String word : words) {
          if (!uniqueWords.contains(word)) {
            uniqueWords.add(word);
          }
        }
        line = reader.readLine();
      }
    }
    Collections.sort(uniqueWords);
    System.out.println(uniqueWords);

  }
}

Old Java, using crappy low-level external loop

# After compilation,
java OldJavaUniqueWords 

Enter filename: data.txt
[aaa, bbb, ccc, ddd]

Java 8, a declarative way using Stream (Monad)

# After compilation,
java Java8UniqueWords 

Enter filename: data.txt
aaa, bbb, ccc, ddd