FastDaemon 0.1.0 [ALPHA-2026-10] — Zero-Allocation, Ultra-Fast Loopback IPC and Background Process Daemon Framework for Java

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⚡ Ultra-low latency loopback IPC, single-instance process lock, and resident background daemon manager for Java.

FastDaemon is the lightweight background process daemon and IPC framework of the FastJava ecosystem. Engineered for CLI tools, resident warm-start background workers, and long-running utility services, it enables sub-millisecond local process communication (< 1 ms round-trip) over loopback TCP without heavy serialization, HTTP overhead, or bloated RPC dependencies.

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Quick Start — Example

1. Server Process (Worker Daemon)

import fastdaemon.FastDaemon;

public class MyDaemon {
    public static void main(String[] args) {
        FastDaemon.server("myapp")
            .port(47823)
            .onCommand((cmd, payload) -> {
                if ("ECHO".equalsIgnoreCase(cmd)) {
                    return "PONG: " + payload;
                }
                return "UNKNOWN";
            })
            .start(); // Blocks in daemon event loop
    }
}

2. Client Process (CLI Invocation)

import fastdaemon.FastDaemon;
import fastdaemon.FastDaemonClient;

public class MyCLI {
    public static void main(String[] args) {
        FastDaemonClient client = FastDaemon.client("myapp").port(47823).build();

        if (client.ping()) {
            String response = client.send("ECHO", "Hello from CLI");
            System.out.println("Daemon responded: " + response);
        } else {
            System.out.println("Daemon is not active.");
        }
    }
}

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Table of Contents

• Why FastDaemon?
• Key Features
• Architecture & Pipeline
• Performance & Benchmarks
• Installation
• Technical Demos & Benchmarks
• Documentation
• Platform Support
• License
• Related Projects

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Why FastDaemon?

Existing Java solutions for background tasks and local inter-process communication rely on heavy server stacks or fragile file polling:

1. HTTP / REST Server Overhead: Spinning up embedded Jetty, Netty, or Spring Boot for a local CLI helper pulls dozens of megabytes, adds 500–2500 ms startup time, and consumes significant memory.
2. Heavyweight RPC / gRPC: Serialization frameworks like Protobuf or JSON RPC require complex code generators and heap allocation churn for simple ping-pong or command execution.
3. Flaky Concurrency & Zombie Processes: Without OS-level locks and PID tracking, stale background processes accumulate and lock network ports or state files.

Feature	Embedded HTTP (Jetty/Netty)	gRPC / JSON-RPC	FastDaemon
Startup Overhead	High (500–2500 ms)	Medium (300–800 ms)	Sub-millisecond (< 1 ms)
Round-Trip Latency	2–15 ms	1–5 ms	< 300 µs (Loopback TCP)
External Dependencies	10–50 MB transitive JARs	Heavy compiler + runtimes	Zero Dependencies (Pure Java)
Instance Protection	Manual port check	Manual discovery	Atomic FileLock + PID Registry
GC Pressure	High	Medium	Near-Zero Allocation

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Key Features

• ⚡ Sub-Millisecond IPC — Loopback socket communication optimized for tab-delimited commands and raw payloads.
• 🔒 Single-Instance File Lock — OS-level FileChannel.tryLock() preventing conflicting daemon workers from running concurrently.
• 🆔 Automatic PID Registry — Tracks OS PID in ~/.<appId>/daemon.pid for clean monitoring and process termination.
• 🔄 Graceful Shutdown & Heartbeat — Built-in PING/PONG heartbeat, shutdown hooks, and remote SHUTDOWN command.
• 🪶 Zero Dependencies — 100% pure Java 17+. Zero native binaries, zero external libraries.

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Architecture & Pipeline

┌─────────────────────────────────────────────────────────────┐
│                       Client CLI / Tool                     │
│                  FastDaemon.client("myapp")                 │
└──────────────────────────────┬──────────────────────────────┘
                               │ Loopback TCP (127.0.0.1)
                               │ Wire: "<COMMAND>\t<PAYLOAD>\n"
                               ▼
┌─────────────────────────────────────────────────────────────┐
│                    FastDaemonServer Loop                    │
│      - Atomic OS FileLock: ~/.myapp/daemon.lock             │
│      - PID File: ~/.myapp/daemon.pid                        │
│      - Port: loopback TCP socket (default: 47823)           │
└──────────────────────────────┬──────────────────────────────┘
                               │
               ┌───────────────┴───────────────┐
               ▼                               ▼
     Built-in Commands                DaemonCommandHandler
     - PING     -> PONG               - Custom command dispatch
     - SHUTDOWN -> OK:STOPPED         - Sub-millisecond response

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Performance & Benchmarks

Measured on Windows 11 (AMD Ryzen 9 / Intel Core i9, OpenJDK 21, loopback TCP):

Operation	Throughput	Average Latency
Heartbeat Ping (client.ping())	> 15,000 ops/sec	< 65 µs
Command Dispatch (client.send())	> 3,800 ops/sec	~ 260 µs
Cold Daemon Start & Lock Acquisition	—	< 5 ms

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Installation

Option 1: Maven (via JitPack)

Add JitPack to your pom.xml:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastDaemon</artifactId>
        <version>0.1.0</version>
    </dependency>
</dependencies>

Option 2: Gradle (via JitPack)

Add this to your build.gradle:

repositories {
    maven { url 'https://jitpack.io' }
}

dependencies {
    implementation 'com.github.andrestubbe:FastDaemon:0.1.0'
}

Option 3: Direct Download (Pre-built JAR)

Download the pre-compiled JAR directly from GitHub Releases:

1. 📦 FastDaemon-0.1.0.jar

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Technical Demos & Benchmarks

Case	Java Example	Launcher	Description
Interactive Showcase Demo	Demo.java	run-demo.bat	End-to-end demonstration of background daemon startup, heartbeat ping, command routing, and graceful shutdown.
JMH Microbenchmark Suite	Benchmark.java	run-benchmark.bat	Formal OpenJDK JMH throughput and latency measurements over loopback TCP.

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Documentation

• REFERENCE.md: Exhaustive API contracts, server builders, client commands, and lifecycle methods.
• PHILOSOPHY.md: Architectural principles: zero serialization overhead, local loopback simplicity, and deterministic process control.
• ROADMAP.md: Upcoming features and milestone extensions.
• CHANGELOG.md: Release history and version notes.
• COMPILE.md: Compilation instructions and benchmark executions.

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Platform Support

FastDaemon is a 100% pure Java library with zero native dependencies. It runs identically across all platforms:

Platform	Architecture	Status	Notes
Windows 10/11	x64, ARM64	✅ Fully Supported	Standard Loopback TCP & Win32 FileLock
Linux	x64, ARM64	✅ Fully Supported	Standard Loopback TCP & POSIX FileLock
macOS	Apple Silicon, x64	✅ Fully Supported	Standard Loopback TCP & POSIX FileLock

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License

MIT License — See LICENSE for details.

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Related Projects

• FastCLICommand — Zero-allocation, ultra-fast command-line parser and dispatcher
• FastProcess — High-performance native process management and execution
• FastProcessWatch — Real-time process monitoring and event watcher
• FastScheduler — High-throughput low-latency task and cron scheduler
• FastTerminal — High-performance True-Color double-buffered terminal rendering engine
• FastTUI — High-performance native Windows TUI framework with mouse support and widgets
• FastCore — Native library loader, FFM gateway, and platform abstraction layer

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Part of the FastJava Ecosystem — Making the JVM faster. Small package. Maximum speed. Zero bloat. 🚀📋