Java Utililty Methods File Read via ByteBuffer

ByteArrayOutputStream output = new ByteArrayOutputStream(4096);
BufferedInputStream input = null;
try {
    input = new BufferedInputStream(new FileInputStream(file));
    byte[] buffer = new byte[2048];
    for (;;) {
        int len = input.read(buffer);
        if (len == (-1))
...

FileInputStream inputStream = new FileInputStream(file);
FileChannel channel = inputStream.getChannel();
ByteBuffer buffer = ByteBuffer.allocate((int) channel.size());
channel.read(buffer);
channel.close();
inputStream.close();
return new String(buffer.array());

RandomAccessFile raf = new RandomAccessFile(file, "r");
byte[] res = readStream(raf.getChannel());
raf.close();
return res;

DataInputStream dataInputStream = null;
try {
    int byteCount = (int) file.length();
    FileInputStream fileInputStream = new FileInputStream(file);
    dataInputStream = new DataInputStream(fileInputStream);
    final byte[] bytes = new byte[byteCount];
    dataInputStream.readFully(bytes);
    return ByteBuffer.wrap(bytes);
...

java.io.FileInputStream fis = new java.io.FileInputStream(file);
java.nio.ByteBuffer buffer = java.nio.ByteBuffer.allocate(PAGE_SIZE);
java.nio.channels.ReadableByteChannel channel = java.nio.channels.Channels.newChannel(fis);
int count = 0;
while (count >= 0) {
    count = channel.read(buffer);
    if (count > 0 && !buffer.hasRemaining()) {
        java.nio.ByteBuffer biggerBuffer = java.nio.ByteBuffer.allocate(buffer.limit() + PAGE_SIZE);
...

if (filename != null) {
    byte[] bytes = getBytes(filename);
    return new String(bytes);
return null;

return readFile(new File(filename));

ByteBuffer buf = null;
FileChannel fc = null;
try {
    FileInputStream fis = new FileInputStream(fileName);
    fc = fis.getChannel();
    int size = (int) fc.size();
    buf = readFileFragment(fc, 0, size);
} catch (FileNotFoundException ex) {
...

return readFile(filename, false);

String readString = "";
RandomAccessFile file = new RandomAccessFile(filePath, "r");
FileChannel channel = file.getChannel();
ByteBuffer buffer = ByteBuffer.allocate(1024);
while (channel.read(buffer) > 0) {
    buffer.flip();
    for (int i = 0; i < buffer.limit(); i++)
        readString += (char) buffer.get();
...