IO

Relationship between Java I/O and system calls, BIO/NIO/AIO classification, comparison, and references.

Traditional server-side programming with BIO and its blocking points.

Asynchronous NIO classes and AsynchronousFileChannel examples for reading and writing with Future polling and CompletionHandler callbacks.

Basic concepts: input/output, streams, and I/O for different purposes.

Basic Buffer usage and the meanings of capacity, position, and limit.

NIO vs BIO and common questions about channel reads, selector.select, and SelectionKey.OP_WRITE.

1. Example: server and client. 2. Reference.

Byte streams with InputStream and OutputStream, and character streams with Reader and Writer.

Basic Channel usage.

What serialization is, a custom ByteBuffer-based serialization rule, and a complete custom Serializer example.

Writing, reading, and metadata for file streams.

Check whether a file exists, create directories, copy files, move or rename files, delete files, and recursively traverse files.

For servers, periodically clear idle channels; for clients, detect disconnected sessions and whether to reconnect.

1. Example: server and client. 2. Reference.

Basic concepts: Channel and Buffer, Channel, Buffer, NIO, and Selector.

What sticky packets and split packets are, why the phenomenon appears with TCP byte streams, and how application-layer framing solves it.

What Path is, absolute paths, and relative paths.

1. Example: server and client. 2. Reference.