Firmware update:

To make your ESP32 development board ready to support programming in Java, you need update JOSH firmware into the board at first:

• LyraT-Mini board JOSH firmware binary update guide: Click here
• WROVER-KIT board JOSH firmware binary update guide: Click here

JOSH Application Developement Guide

After JOSH firmware updated, you can start to develop ESP32 application in Java: Click here

Building JOSH ESP32 from source code:

JOSHVM building instructions for WROVER-KIT and LyraT-Mini: Click here