ADDITIONAL SYSTEM INFORMATION :
Windows 10 Java 17.0.4.1

A DESCRIPTION OF THE PROBLEM :
Not a major issue but it will enhance usability

The AsynchronousFileChannel[https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/nio/channels/AsynchronousFileChannel.html] class has 4 methods for I/O 2 for reading and 2 for writing

abstract Future<Integer> read(ByteBuffer dst, long position)
abstract <A> void read(ByteBuffer dst, long position, A attachment, CompletionHandler<Integer,? super A> handler)
abstract Future<Integer> write(ByteBuffer src, long position)
abstract <A> void write(ByteBuffer src, long position, A attachment, CompletionHandler<Integer,? super A> handler)

These 4 methods are also part of the AsynchronousByteChannel interface [https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/nio/channels/AsynchronousByteChannel.html]

Hence making AsynchronousFileChannel implement this interface rather than AsynchronousChannel directly would be more logical as AsynchronousByteChannel extends AsynchronousChannel anyway so developers don't have to change code anywhere

Another advantage of doing this is that the Channels class[https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/nio/channels/Channels.html] could then work with the AsynchronousFileChannel using its 2 methods

static InputStream newInputStream(AsynchronousByteChannel ch)
static OutputStream newOutputStream(AsynchronousByteChannel ch)

It would be an added bonus