# TODO - JVMRS Project
## Competitive Differentiation Roadmap
### Unique JVMRS Features (vs HotSpot, OpenJ9, GraalVM)
- [x] Expand Rust-specific memory safety advantages in documentation
- [x] Showcase WebAssembly native execution scenarios
- [x] Highlight deterministic execution for blockchain/reproducible computing
- [x] Demonstrate polyglot capabilities beyond standard JVMs
- [ ] Optimize for embedded/IoT scenarios with no_std builds
- [ ] Develop comprehensive benchmarks against HotSpot/OpenJ9
## Active Priorities
### Implemented Improvements (This Iteration)
- [x] Harden descriptor parsing to handle malformed descriptors safely without panics
- [x] Extend descriptor parameter parsing to support array parameters
- [x] Make classpath parsing trim whitespace and ignore empty segments
- [x] Implement missing stack manipulation opcodes (pop2, dup2, dup2_x1, dup2_x2, swap)
- [x] Implement missing arithmetic/logic opcodes (ishl, ishr, iushr, iand, ior, ixor)
- [x] Implement type conversion opcodes (i2l, i2f, i2d, l2i, etc.)
- [x] Implement missing long arithmetic (ladd, lsub, lmul, ldiv)
- [x] Implement float/double arithmetic (fadd, dadd, fsub, dsub, fmul, dmul, fdiv, ddiv, frem, drem, fneg, dneg)
- [x] Implement comparison opcodes (lcmp, fcmpl, fcmpg, dcmpl, dcmpg)
- [x] Implement control flow opcodes (tableswitch, lookupswitch, if_acmp*, etc.)
- [x] Add unit tests for control flow opcodes
### High (Next Sprint)
- [ ] Add support for threads and concurrency
- [x] Set up CI/CD pipeline
- [x] Test with more complex Java examples
- [x] Expand JIT bytecode coverage
### Medium
- [x] Implement JNI (Java Native Interface)
- [x] Add support for annotations
- [x] Add code coverage reporting
- [x] Profile and optimize class loading
- [x] Optimize instruction dispatch
### Low / Backlog
- [x] Create REPL for interactive JVM exploration
- [x] Add support for generics (type erasure)
- [x] Implement serialization/deserialization (binary JVRS format, is_serializable_class)
- [x] Replace placeholders with real implementations (reflection, serialization, JIT fallback)
- [x] Sufficient test coverage (68+ unit tests, doctests)
- [x] Create visualization tools for JVM internals
- [x] Create documentation website
- [x] Set up fuzz testing for class file parser
- [x] Add hot code reloading
- [x] Add proxy-based AOP support
- [ ] Create Kubernetes operator
---
## Future Competitive Differentiation
### Rust Ecosystem Integration
- [x] Direct Rust-Java interop without JNI overhead
- [x] Rust crate integration system for Java extensions
- [x] Compile-time Java-to-Rust binding generation (scaffold: jvmrs-bindgen)
- [x] Rust macro system for Java class definitions (jvmrs-macros crate)
### Next-Generation Deployment Targets
- [x] WASI (WebAssembly System Interface) support
- [x] Browser-based Java execution via WASM
- [x] Edge computing optimizations
- [x] Serverless platform optimizations
### Developer Experience Advantages
- [ ] IDE plugins for cross-language debugging
- [x] Hot reloading for Java/Rust hybrid development
- [x] Performance profiling with Rust tooling integration
- [x] Rust documentation system for Java APIs
### Specialized Use Cases
- [x] Blockchain/deterministic execution mode
- [x] Real-time systems with guaranteed pause times
- [x] High-frequency trading with ultra-low latency
- [ ] Safety-critical systems with formal verification
---
## Completed ✓
### Core JVM
- [x] Implement missing JVM opcodes (~60% coverage)
- [x] Proper error handling with custom error types
- [x] Garbage collection (mark-and-sweep, generational)
- [x] Arrays (newarray, anewarray, iaload, iastore, etc.)
- [x] Strings and string operations
- [x] Class inheritance and polymorphism
- [x] Interface support (invokeinterface)
- [x] Class loading from classpath
- [x] Exception handling (division by zero, array bounds)
- [x] Native method interface
- [x] Synchronization (monitorenter/monitorexit)
- [x] Reflection API (Interpreter: new_instance, get/set_field_value, invoke_method, get_object_class; ReflectionApi delegates)
- [x] Logging/debugging capabilities
- [x] Benchmark suite
- [x] Unit tests for each module
### Compilation & Backends
- [x] JIT compilation (Cranelift)
- [x] Tiered compilation (interpreter → JIT)
- [x] AOT compilation (.o files)
- [x] LLVM IR backend
- [x] WebAssembly backend
### Memory & GC
- [x] Generational GC (young/old)
- [x] Arena-based allocators
### Embedding & Interop
- [x] C API (FFI) for embedding
- [x] Polyglot Java/Rust interop
- [x] Async I/O (tokio)
- [x] SIMD vectorization
- [x] Truffle-style API
- [x] no_std support
### Developer Tools
- [x] Integrated profiler (flame graphs)
- [x] Time-travel debugging
- [x] Security instrumentation
- [x] Deterministic execution mode
- [x] Fast class loading (.jvmc cache)
---
## Infrastructure
| CI/CD pipeline | Done (.github/workflows/ci.yml) |
| Code coverage | Done (cargo-llvm-cov in CI) |
| Unit tests | 68+ tests, all passing |
| Doctests | Extensions example runs (no longer ignored) |
| API documentation | Pending |
| Architecture diagrams | Pending |
---
## Reference
See `docs/structure.md` for source code layout and module organization.