A VS Code extension which provides one-click, review-before-you-commit Java to Kotlin migration inside VS Code. The extension utilises LLMs to provide idiomatic conversion suggestions, helping Java developers migrate to Kotlin.
j2k_demo_short.mp4
In the demo, a new project is opened, Kotlin is configured automatically, and converting a singular file/multiple files in succession is demonstrated. The accept/reject workflow is also demonstrated, with the ability to make desired changes before committing the changes. Additionally, integration with Git is demonstrated, so that version control history is preserved across the conversion.
One of the following LM providers should be configured:
- GitHub Copilot Chat installed in VS Code and signed in.
- Ollama/LM Studio running locally and the chosen model pulled.
- A valid API key for OpenAI/OpenRouter.
Download the latest .vsix from the releases section of this repository. Then, navigate to the Extensions tab in VS Code, click the three small dots on the top right corner of the tab, and choose Install from VSIX.... Then, select the newly downloaded J2K VSIX to finish the installation.
To report a bug or an issue, please use GitHub issues and log an issue under this repository. When reporting, include as much detail as possible (steps to reproduce, expected vs. actual behaviour, screenshots, etc.).
Contributions are welcome! If you'd like to improve the project, please fork the repository and create a pull request with your changes. Make sure your code is formatted and linted (npm targets exist for these actions) and includes relevant documentation updates. For larger contributions, consider opening an issue first.
Right click a .java file, a selection of files or a folder to convert all selected .java files.
A side-by-side diff opens so you can review and edit the generated Kotlin before saving changes.
Accept the changes to replace the Java file with its Kotlin replacement, or cancel to close the preview with no changes.
Commit the conversion as a rename and modification which keeps commit history intact. Currently supported version control software: Git
Automatically configure Kotlin for your project. Currently supported build systems: Gradle
Use popular models seamlessly to power Kotlin conversion. Currently supported: OpenAI, OpenAI-like (OpenRouter, LM Studio), Ollama, VSCode-integrated Github Copilot
This extension contributes the following settings:
j2k.provider: The LLM backend to use for the Java to Kotlin conversion. Default:GitHub Copilotj2k.model: The model tag to use with the selected provider. Default:codellama:instruct.j2k.ollama.baseUrl: The base URL of the target instance, when the provider selected is Ollama.j2k.openRouter.baseUrl: The base URL of the target instance, when the provider selected is OpenRouter.j2k.apiKey: The API key to use with the selected provider (stored in VS Code Secrets).
Upcoming!
[Note: this is a copy of the README under extension/.]