jkey

A lightweight, Redis-inspired key-value store written in Java.

Features

Concurrent connections via Java 21 virtual threads
Commands: PING, GET, SET, DEL, EXISTS
Pluggable Store interface for swappable storage backends

Requirements

Java 21+

Building

Compile all sources from the project root:

javac -d out shared/*.java server/*.java client/*.java

Running

Start the server (default port 8080):

java -cp out server.Server

Or specify a custom port:

java -cp out server.Server 7379

Run the client:

java -cp out client.Client <command> [arguments]

Commands

Command	Usage	Description
`ping`	`ping`	Health check
`set`	`set <key> <value>`	Store a value
`get`	`get <key>`	Retrieve a value
`delete`	`delete <key>`	Remove a key
`exists`	`exists <key>`	Check if a key exists

Examples

java -cp out client.Client ping
# OK

java -cp out client.Client set hello world
# OK

java -cp out client.Client get hello
# OK
# world

java -cp out client.Client exists hello
# OK

java -cp out client.Client delete hello
# OK

java -cp out client.Client get hello
# NOT_FOUND

Protocol

jkey uses a simple binary protocol over TCP.

Request:

[1 byte]  command
[4 bytes] key length
[N bytes] key
[4 bytes] value length  (SET only)
[M bytes] value         (SET only)

Response:

[1 byte]  status (OK=0x0, NOT_FOUND=0x1, ERROR=0x2)
[4 bytes] value length  (GET only, on OK)
[N bytes] value         (GET only, on OK)

printchard/jkey

README