https://github.com/chaoyangnz/zava

Mini Java VM in Zig
https://github.com/chaoyangnz/zava

bytecode java java-8 jvm zig

Last synced: 3 months ago
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Mini Java VM in Zig

• Host: GitHub
• URL: https://github.com/chaoyangnz/zava
• Owner: chaoyangnz
• Created: 2022-08-23T08:56:50.000Z (over 2 years ago)
• Default Branch: master
• Last Pushed: 2024-08-12T09:20:38.000Z (6 months ago)
• Last Synced: 2024-10-21T04:01:21.744Z (3 months ago)
• Topics: bytecode, java, java-8, jvm, zig
• Language: Zig
• Homepage:
• Size: 52.8 MB
• Stars: 9
• Watchers: 3
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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• awesome-zig - zava🗒️Java VM / bytecode interpreter in Zig

README

        
# zava

Mini Java VM in Zig `v0.13.0`

## What it is

Zava is a Java* VM implementation in Zig. This is a sister project of [Gava](https://github.com/chaoyangnz/gava) which is using Go.

The goal of Zava is to implement a couple of features which are not capable of doing by Go, such as GC and fine control of memory allocation.

The reference of the implement is [JVM Spec 8 edition](https://docs.oracle.com/javase/specs/jvms/se8/html/) and it is supposed to be compatible with Java 8 bytecode.

--- 

> \* JAVA is a trademark of Oracle America, Inc.

## Roadmap

Feature:

- [x] type system definition

- [x] class file parser

- [x] instructions interpretion 

- [x] native methods bridge to support HelloWorld

- [x] class loading

  - [x] bootstrap class loader

  - [x] user defined class loader

- [x] string pool

- [x] basic reflection support (Class, Field, Method, Consutructor)

- [ ] multi-thread and concurrency

- [ ] garbage collector

- [ ] profiling and Debugger integration

Non-functional:

- [ ] sufficent unit test coverage

- [ ] code readability and clear documentation of high-level design

- [ ] mini ebook to describe how to evolve a mini VM from scratch

- [ ] VSCode debugging extension

## Get started

Download [JDK](https://github.com/chaoyangnz/zava/wiki/JDK) and extract to `jdk` folder.

The default class path is `examples/classes` and `jdk/classes`, so any classes located in the path can be loaded by `zava`.

- HelloWorld

```

zig build

./zava HelloWorld

```

![demo](demo.gif)

## Debugging

A VS code launch.json is configured for your debugging.

And after running the program, a `zava.log` is produced to trace the execution.

- info level: only method calls are logged

- debug level: per instruction executions are also logged with the context