import java.io.*;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

/**
 * @author lesinsa on 30.05.2015.
 */
public class Main {

    public static final String TEST_FILE = "test.txt";
    public static final int NLINES = 250000;

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

        long tw = System.currentTimeMillis();
        try (FileOutputStream outputStream = new FileOutputStream(TEST_FILE)) {
            for (int i = 0; i < NLINES; i++) {
                Writer writer = new BufferedWriter(new OutputStreamWriter(outputStream), 4 * 1024);
                writer.write(UUID.randomUUID().toString());
                writer.write(" ");
                writer.write(UUID.randomUUID().toString());
                writer.write(" ");
                writer.write(UUID.randomUUID().toString());
                writer.write(" ");
                writer.write(UUID.randomUUID().toString());
                writer.write(" ");
                writer.write(UUID.randomUUID().toString());
                writer.write("\n");
                writer.flush();
            }
        }
        tw = System.currentTimeMillis() - tw;
        System.out.println(String.format("Written %d line by %d ms", NLINES, tw));

        for (int i = 0; i < 25; i++) {
            long t = System.currentTimeMillis();
            ArrayList<String> strings = new ArrayList<>();
            try (FileInputStream inputStream = new FileInputStream(TEST_FILE)) {
                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream), 32 * 1024);
                String s = reader.readLine();
                while (s != null) {
                    strings.add(s);
                    s = reader.readLine();
                }
            }
            t = System.currentTimeMillis() - t;
            System.out.println(String.format("Read %d line by %d ms", strings.size(), t));
        }


        System.out.println();
        System.out.println("Reading using Java NIO");


        for (int i = 0; i < 25; i++) {
            long t = System.currentTimeMillis();
            List<String> stroki = Files.readAllLines(Paths.get(TEST_FILE), Charset.defaultCharset());
            t = System.currentTimeMillis() - t;
            System.out.println(String.format("Read %d line by %d ms", stroki.size(), t));
        }
    }
}

import java.io.*;
import java.nio.charset.Charset;
import java.util.ArrayList;

public class Main {

    public static final String TEST_FILE = "war_and world.txt";
    private static final String TEST_OUTPUT_FILE = "war_and_world.utf8.txt";
    public static final String INPUT_ENCODING = "utf-16";
    public static final String OUTPUT_ENCODING = "utf-8";

    public static void main(String[] args) throws IOException {
        for (int i = 0; i < 10; i++) {
            long t = System.currentTimeMillis();
            ArrayList<String> strings = new ArrayList<>();
            try (FileInputStream inputStream = new FileInputStream(TEST_FILE)) {
                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(inputStream, Charset.forName(INPUT_ENCODING)));
                String s = reader.readLine();
                while (s != null) {
                    strings.add(s);
                    s = reader.readLine();
                }
            }
            t = System.currentTimeMillis() - t;
            System.out.println(String.format("Read %d line by %d ms", strings.size(), t));

            long tw = System.currentTimeMillis();
            try (FileOutputStream outputStream = new FileOutputStream(TEST_OUTPUT_FILE)) {
                BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outputStream, OUTPUT_ENCODING));
                for (String string : strings) {
                    writer.write(string);
                    writer.write("\n");
                }
            }
            tw = System.currentTimeMillis() - tw;
            System.out.println(String.format("Written %d line by %d ms", strings.size(), tw));
            System.out.println();
        }
    }
}