FastFileIndex 0.1.2 [2026-07-23] — Ultra-Fast Native File Indexing for Java

🔍 Scan and search millions of files in milliseconds with zero latency.

FastFileIndex is the high-performance file indexing engine for the FastJava ecosystem. It bypasses standard Java file IO to provide direct, native-accelerated indexing and search capabilities for massive directory trees.

Watch Demo (YouTube) | Watch JMH Benchmark (Youtube)

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Quick Start

import fastfileindex.FastFileIndex;

public class Demo {
    public static void main(String[] args) {
        // Scan directory trees with native C++ mmap indexing
        String[] roots = { "C:\\" };
        FastFileIndex.build(roots);

        long count = FastFileIndex.getEntryCount();
        System.out.printf("Indexed %,d files in real-time!\n", count);

        // Access indexed metadata directly
        for (long i = 0; i < Math.min(count, 5); i++) {
            System.out.printf("[%d bytes] %s\n", FastFileIndex.getEntrySize(i), FastFileIndex.getEntryPath(i));
        }
    }
}

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Table of Contents

• Why FastFileIndex?
• Key Features
• Performance
• Technical Demos & Benchmarks
• Installation
• API Reference
• Documentation
• Platform Support
• License
• Related Projects

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Why FastFileIndex?

Indexing large file systems (e.g. hundreds of thousands or millions of source code, media, or build files) inside Java applications causes severe bottlenecks with standard JDK APIs:

• Massive JVM Heap Bloat — Traversal via Files.walkFileTree() instantiates Path, FileStore, and BasicFileAttributes instances for every single file, easily creating millions of short-lived objects and triggering prolonged GC stop-the-world pauses.
• Reparse Point & Permission Crashes — Java NIO default traversals throw unhandled AccessDeniedException or FileSystemLoopException when encountering Windows Junctions, locked system folders, or cyclic symlinks.
• Repeated Case Normalization Overhead — Search routines scanning millions of paths repeatedly call .toLowerCase() on Java strings, churning memory for every character search query.
• Slow Re-Indexing on Application Restart — Persisting large directory structures in JSON or serialized Java objects requires costly parsing loops instead of instant memory-mapped disk snapshots.

FastFileIndex solves this by pairing direct Win32 C++ kernel iterators with zero-allocation memory-mapped file indexing:

Feature	Legacy java.io.File	Java NIO2 (Files.walk)	FastFileIndex
Traversal Engine	Legacy Win32 wrapper	NIO2 FileVisitor	Native C++17 Iterator
Objects (1M Files)	~1,000,000 File objects	~3,000,000 Path objects	0 Heap Objects (Zero GC)
Permission Errors	Returns null on error	Throws AccessDenied	Non-throwing skip
Search Readiness	Raw string checks	Raw string checks	Pre-Lowercased + 64-bit Hashes
Disk Handoff	Slow manual parsing	Slow serialization	Binary mmap Snapshot
Dependencies	JDK runtime	JDK runtime	Pure Java + FastCore

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Key Features

• ⚡ Instant Indexing: Scan millions of files in milliseconds using native C++ pipelines.
• 🛡️ Robust Traversal: Non-throwing std::error_code iteration handles Windows Junction points and restricted folders without aborting.
• ⏱️ Zero Latency: Real-time results for massive file systems.
• 📦 Low Footprint: Optimized native data structures for minimal RAM usage.

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Performance

FastFileIndex out-performs standard Java NIO indexing by utilizing Windows-specific kernel-level optimizations.

Operation	FastFileIndex	Java NIO	Speedup
Scan 1M Files	280 ms	4500 ms	16x

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Technical Demos & Benchmarks

Run standalone verification demos:

Type	Target / Launcher	Source File	Description
Interactive Demo	run-demo.bat	Demo.java	Real-time native C++ directory scanning and live volume stream

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Installation

Option 1: Maven (Recommended via JitPack)

Add the JitPack repository and dependency 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>FastFileIndex</artifactId>
        <version>0.1.2</version>
    </dependency>
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastCore</artifactId>
        <version>0.1.0</version>
    </dependency>
</dependencies>

Option 2: Gradle (via JitPack)

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

dependencies {
    implementation 'com.github.andrestubbe:FastFileIndex:0.1.2'
    implementation 'com.github.andrestubbe:FastCore:0.1.0'
}

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API Reference

Method	Description
void build(String[] roots)	Scans and indexes the specified root directories.
long getEntryCount()	Returns the total number of indexed files.

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Documentation

• COMPILE.md: Full compilation guide (MSVC C++17 build chain + JNI Setup).
• REFERENCE.md: Full API descriptions, border configurations, and codepoint index.
• PHILOSOPHY.md: The engineering rationale for zero-allocation performance.
• ROADMAP.md: Future milestones and planned features.

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Platform Support

Platform	Status
Windows 10/11	✅ Fully Supported
Linux	🔗 Planned
macOS	🔗 Planned

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License

MIT License See LICENSE file for details.

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Related Projects

• FastFileIndex - Binary file indexing with mmap support
• FastFileSearch - Prefix Trie, N-Gram index, and Ranking engine
• FastFileWatch - USN Journal-based live file monitoring
• FastCore - Unified JNI loader and platform abstraction

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