Автор: Крейг Уоллс
Год: 2022

AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(Paths.get("file.txt"));
fileChannel.read(buffer, 0, buffer, new CompletionHandler<>() {
    public void completed(Integer result, ByteBuffer buffer) {
        System.out.println("Data read: " + new String(buffer.array()));
    }
    public void failed(Throwable exc, ByteBuffer buffer) {
        exc.printStackTrace();
    }
});

ByteBuffer buffer = ByteBuffer.allocate(1024);
fileChannel.read(buffer);
buffer.flip();  // Подготавливает буфер для чтения
System.out.println("Buffer data: " + new String(buffer.array()));

AsynchronousFileChannel sourceChannel = AsynchronousFileChannel.open(Paths.get("source.txt"));
AsynchronousFileChannel destChannel = AsynchronousFileChannel.open(Paths.get("dest.txt"), StandardOpenOption.WRITE);
sourceChannel.transferTo(0, sourceChannel.size(), destChannel);

Автор: Капель Е.
Год: 2019