surreal cradle
Yes, we're perverts. Link: https://github.com/nectostr/ZeroJVM/tree/main
We present you a partial implementation of a Java Virtual Machine for Flipper Zero devices 😄
It successfully compiles to 16KB fap file and is capable of:
- basic Java control instructions (stack operations, program flow control)
- basic OOP (static & instance fields and methods, but working with a single Entrypoint class so far (but can spawn new instances, lol))
- byte/short/int/float math
- Text output to the display
- Flipper Zero speaker control (yes, from Java)
How does it work:
You compile valid Java single class named Entrypoint with a Java compiler (javac) and upload resulting Entrypoint.class file to SD card root. ZeroJVM will find this file, locate public static void main and start execution.
See the repo: README.md, examples, and Makefile.
Q&A:
Q: Why the hell did you do that?
A: Programming courses, nothing interesting. Nothing production-oriented.
Q: Can I use it for my Java code?!
A: Yes, you can, No, you shouldn't, lol.
Most likely no without changes. It's a lazy and partially finished implementation of the JVM, we didn't implement everything (moreover, we implemented a rather small part of reference JVM), so read the examples and adjust your code as instructed.
Q: Do you plan to implement more features, develop, extend, etc?
A: 99% no, feel free to fork and extend.
Features to implement to make it stable:
- Dynamic class loading (for imports of other classes)
- Double/Long math
- Reference types instructions (yes, we were very lazy, sorry)
- Proper implementation of Object and System
Fortunately, if you at least partially know how it works, it probably would be pretty easy.
Q: Any technical details about the repo I should know?
A: Yes:
- Read makefile, target 'x86' is for x86 Linux PCs to debug, target 'flipper' and 'launch' are for compilation and uploading to the flipper
- No garbage collection at all
- Interpreter instead of JIT
- Good luck
marsh canyon
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