JVSplit Blog Post

In my ongoing journey to master AI, I recently set myself a challenge: Could I develop a fully functional Java application without manually writing the code? Iโ€™m excited to share that the result, JVSplit (Java Video Split), is not only functional but, in many ways, outperforms several free alternatives Iโ€™ve tested on the Microsoft Store.

The Vision: JVSplit

The goal was clear: create a tool that allows users to navigate long videos, mark specific segments, and export them. The twist? Users should have the flexibility to either join those segments into a single file or export them individually.

Phase 1: The Blueprint

I started by using Gemini Pro as a lead architect. Before a single line of code was generated, we discussed:

  • Project Structure: Organizing the logic for scalability.
  • The Tech Stack: Deciding on the best libraries and external tools (like VLCJ for playback and FFmpeg for processing) to ensure the app remained lightweight yet powerful.

Phase 2: Feature Engineering

Precision is everything in video editing. We worked through the logic of features that make or break an editor:

  • Frame-Accurate Navigation: Implementing controls to jump +/- 5, 1, and even 0.1 seconds.
  • Project Management: Building the “Create/Open/Save” workflow so users don’t lose their progress.
  • The Timeline: Designing a custom UI component to manage segments visually.

Phase 3: The Iterative Build

This was the most rewarding part of the journey. Working within the Eclipse IDE, I acted as the “Integrator.” Gemini generated the source code for various modules, and I meticulously added them to the project, running the app at every stage to verify the behavior.

Instead of mindlessly copying, I focused on the logical flow. When the code was “complete,” the real work began: debugging.

Phase 4: Solving the “Hard” Problems

Even with AI, software development isn’t “magic.” We encountered classic engineering hurdles:

  • Race Conditions: Handling multiple threads to ensure the video engine and the UI didn’t clash.
  • UI Synchronization: Ensuring the timeline and the video player stayed perfectly in sync.
  • Data Integrity: Adding safety checks to prevent users from accidentally overwriting their files.

By iterating on these bugs with the AI, I didn’t just fix the appโ€”I deepened my understanding of how these complex systems interact.

The Verdict

The final version of JVSplit is a testament to what is possible when you combine human intent with AI capabilities. By focusing on prompt engineering, project structure, and rigorous testing, I was able to build a desktop tool that is stable, precise, and genuinely useful. JVSplit-Source.zip (48.2KB)

This project proved that the “No Code” path in Java isn’t about the absence of code; it’s about the presence of better communication between the developer’s vision and the AI’s execution.


Appendix: JVSplit Technical Specifications

To provide a clearer picture of the architecture behind the app, here are the core technical requirements and features we implemented:

Core Tech Stack

  • Language & Framework: Java 21+ using the Swing library for a native desktop UI.
  • IDE: Developed and compiled within the Eclipse IDE.
  • Media Engine: Integrated VLCJ (v4.x) to handle high-performance video playback and frame seeking.
  • Processing Power: Utilizes FFmpeg as the backend engine for all “lossless” cutting and merging operations.

Key Functional Features

  • High-Precision Seeking: Dedicated controls for micro-adjustments at 0.1s, 1s, and 5s intervals, essential for finding the exact frame to cut.
  • Segment Management: A custom-built Timeline Component that features:
    • A visual “Ruler” for time orientation.
    • Unique color-coded segments for easy identification.
    • Context menus for quick actions (Set Start/End, Play Selection, Remove).
  • Project Persistence: Full support for JSON-based project files, allowing users to save their workspace and return to it later.
  • Smart Export Logic:
    • Single File: Uses the FFmpeg concat demuxer to join parts without re-encoding.
    • Multiple Files: Batch exports each marked segment as a standalone video.
  • Safety Protocols: Integrated “File Overwrite” warnings and “Confirmation Dialogs” for segment removal to prevent accidental data loss.

Behind the Scenes

  • Concurrency: Implemented background threading for FFmpeg tasks to ensure the UI remains responsive during the export process.
  • Synchronization: Custom logic to bridge the communication between the VLCJ player state and the Swing Timeline UI.


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