Writing a file with a BufferedWriter and then reading it with a FileChannel

[Steve Myers]

This is a cross-post : stackoverflow

I am doing exercises in a Java book. The exercise is reading back a file containing a number of Strings (with no separater characters) from one file using the binary int lengths of the of the corresponding Strings from another file. I've verified that the files are written correctly by using the author's provided solution as well as my own for the writing class. I have gotten the reading class working by using a BufferedReader to read the strings. The first incarnation of the reader class used a FileChannel, and I'm not understanding why I can't get it working properly with the FileChannel. I'm thinking it has something to do with character encoding. The BufferedWriter is using "UTF-16", which is the default character encoding for the Java language.

Here is the output I am getting. For some reason I am getting a '?' at the beginning of the file which is causing the rest of the problems as you can see.

Length of saying: 44 Saying: ?A nod is as good as a wink to a blind horse
Length of saying: 27 Saying: .Least said, soonest mended
Length of saying: 42 Saying: .There are 10 kinds of people in the world
Length of saying: 50 Saying: .those that understand binary and those that don't
Length of saying: 47 Saying: .You can't amke a silk purse out of a sow's ear
Length of saying: 33 Saying: .Hindsight is always twnty-twenty
Length of saying: 29 Saying: .Existentialism has no future
Length of saying: 43 Saying: .Those who are not confused are misinformed
Length of saying: 32 Saying: .Better untaught that ill-taught

First, here is the code for the writing class which is generating the files:
(I'm aware of the inconsistencies in the code, such as magic numbers, etc. Just would like to get it working first.)

import java.io.*;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import java.nio.file.*;
import java.nio.charset.Charset;

public class WriterOutputToFile {

	public static void main(String[] args) {
		String[] sayings = { "A nod is as good as a wink to a blind horse.",
				"Least said, soonest mended.",
				"There are 10 kinds of people in the world.",
				"those that understand binary and those that don't.",
				"You can't amke a silk purse out of a sow's ear.",
				"Hindsight is always twnty-twenty.",
				"Existentialism has no future.",
				"Those who are not confused are misinformed.",
				"Better untaught that ill-taught." };

		Path dir = Paths.get("d:/java io/");
		
		Path file = dir.resolve("Sayings.txt");
		
		try {
			Files.createDirectories(file.getParent());
		} catch(IOException e) {
			System.err.println("Error craeting directory: " + file.getParent());
			e.printStackTrace();
			System.exit(1);
		}
		try(BufferedWriter fileOut = Files.newBufferedWriter(file,  Charset.forName("UTF-16"))) {
			
			for(int i = 0; i < sayings.length; ++i) {
				fileOut.write(sayings[i]);
			}
		} catch (IOException e) {
			System.err.println("error writing file: " + file);
			e.printStackTrace();
		}
		
		Path fileLength = dir.resolve("SayingsLength.bin");
		ByteBuffer buf = ByteBuffer.allocate(sayings.length * 4);
		IntBuffer intBuf = buf.asIntBuffer();
		
		int[] lengths = new int[sayings.length];
		for(int i = 0; i < lengths.length; ++i) {
			lengths[i] = sayings[i].length();
			intBuf.put(lengths[i]);
		}
		
		try (BufferedOutputStream lengthOut = new BufferedOutputStream(Files.newOutputStream(fileLength))) {
			lengthOut.write(buf.array(), 0, buf.capacity());
			System.out.println("dir createred");
		} catch (IOException e) {
			System.err.println("error writing file: " + file);
			e.printStackTrace();
		}
		
	}
}

And here is the file for reading it using FileChannels for both files:

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.IntBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.ReadableByteChannel;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class ProverbReader {
	public static void main(String[] args) {
		Path sayingsFile = Paths.get("d:/java IO/Sayings.txt");
		Path sayingsLengthFile = Paths.get("d:/java IO/SayingsLength.bin");

		if (!Files.exists(sayingsFile) || !Files.exists(sayingsLengthFile)) {

			System.out.println("One or both files do not exist, exiting program");
			System.exit(1);
		}

		final int SAYINGS_COUNT = 20;
		final int INT_BYTES = 4;
		final int CHAR_BYTES = 2;

		int[] lengths = new int[SAYINGS_COUNT];

		try (ReadableByteChannel sayingsIn = Files.newByteChannel(sayingsFile); ReadableByteChannel lengthsIn = Files.newByteChannel(sayingsLengthFile)) {

			ByteBuffer buf = ByteBuffer.allocate(SAYINGS_COUNT * INT_BYTES);

			while (true) {
				if (lengthsIn.read(buf) == -1)
					break;

				buf.flip();
				int numberRead = buf.remaining() / INT_BYTES;

				int totalChars = 0;
				for (int i = 0; i < numberRead; ++i) {
					lengths[i] = buf.getInt();
					totalChars += lengths[i];
				}

				ByteBuffer strBuf = ByteBuffer.allocate(totalChars * CHAR_BYTES);

				if (sayingsIn.read(strBuf) == -1) {
					System.out.println("A serious error has occured, terminating");
					System.exit(1);
				}

				strBuf.flip();

				char[] charArray = new char[totalChars];

				strBuf.asCharBuffer().get(charArray);

				int count = 0;
				for (int i = 0; i < numberRead; ++i) {
					String saying = String.valueOf(charArray, count, lengths[i]);
					System.out.printf("Length of saying: %3d Saying: %s%n", lengths[i], saying);
					count += lengths[i];
				}
				buf.clear();
			}
		} catch (IOException e) {
			e.printStackTrace();
			System.exit(1);
		}
	}
}