java2pyi

Java‑to‑PYI is a Rust tool that parses Java source into a preprocessed AST and generates Python stub files (.pyi) with type definitions only. It was originally designed to generate class declarations to provide accurate type hints in the Telegram codebase when developing Exteragram plugins.

Installation from crates.io

cargo install java2pyi

Building from source code and installation steps

1. Clone this repo

git clone https://github.com/n08i40k/java2pyi

2. Compile and install

cargo install --path .

Usage example

1. Clone OpenJDK source code (required for all use-cases, otherwise, non-promitive java types won't be resolved)

git clone https://github.com/openjdk/jdk

2. Remove sample file from OpenJDK source code

rm ./jdk/src/java.base/share/classes/java/lang/snippet-files/ProcessExamples.java

3. Clone Telegram for Android source code

git clone https://github.com/DrKLO/Telegram

4. Create directory for stub files

mkdir stubs

5. Start generator

java2pyi -i ./jdk/src/java.base/share/classes/java/ -i ./Telegram/TMessagesProj/src/main/java/ -o ./stubs

Where -i is directories with .java files and -o is output directory for generated stubs.