FlintESPJVM

FlintESPJVM brings the power of Java to ESP32 devices by implementing FlintJVM on the ESP-IDF framework. This allows you to run and debug Java programs directly on the ESP32 hardware.

Key Features

• Supports most Java bytecode instructions.
• Supports debugging with FlintJVM Debug VS Code extension via serial port.

How to use

1. Supported Boards

FlintESPJVM is compatible with a variety of ESP32 boards, including:

• Generic ESP32 Boards.
• ESP32-C3FH4.
• ESP32-C6FH4.
• ESP32-C6FH8.
• ESP32-S2FN4R2.
• ESP32-S3FH4R2.
• ESP32-S3N4RX.
• ESP32-S3N8RX.
• ESP32-S3N16RX.

2. Flashing the Firmware

To get FlintESPJVM up and running on your board:

• Quick Flash: Use the ESP Web Tool for an easy, browser-based flashing experience.
• Manual Build: Prefer building it yourself? Utilize the ESP-IDF framework to compile and flash the project manually.

3. Building Java Projects for FlintESPJVM

To develop Java applications for FlintESPJVM:

• Project Setup: Use the FlintJDK module to access core Java libraries compatible with FlintJVM.
• Debugging: Install the FlintJVM Debug extension in VS Code.

Refer to the FlintExample project, which provides a simple and clear template to help you get started with building Java apps for FlintJVM.

4. Dependencies and Cloning

• This project requires ESP-IDF v5.5.0 or later to build.
• Run the following command to clone this repository and include all dependent submodules:

> git clone --recurse-submodules https://github.com/FlintVN/FlintESPJVM.git

Benchmark

Below are the performance benchmarks of several different programming languages on the ESP32, focusing on.

• Execution time of 10 million iterations using for and while loops.

• Maximum toggling frequency of GPIO when driven by the CPU.

  Platform	for loop (10M)	while loop (10M)	GPIO toggle frequency
  C/IDF v5.5.0	375 ms	375 ms	2.2 MHz
  Java/FlintESPJVM v0.0.11	9254 ms	9254 ms	295 KHz
  MicroPython v1.26.0	43677 ms	79582 ms	107 KHz
  C#/NanoFramework v1.12.4	77656 ms	77660 ms	2.4 KHz

The source code of this test can be viewed at ESP32-Perfomance.

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Elevate your ESP32 projects by harnessing the robustness of Java with FlintESPJVM.