Which one should I pick for a new project?

I can only help you understand the specific technical details of greenrobot/eventbus and stleary/json-java—they serve fundamentally different purposes, so the choice depends on what your project needs:

greenrobot/eventbus is an event pub/sub library. Pick it if you need:

• Decoupled communication between components (Activities, Fragments, Services, threads)
• A lightweight event dispatch system (~60 jar)
• Advanced features like thread modes, sticky events, and subscriber priorities

stleary/json-java is a JSON parser/generator. Pick it if you need:

• JSON serialization and deserialization
• Support for JSON objects and arrays in Java
• Conversion between Java objects and JSON formats

They're complementary, not competing—you might use both in the same project. EventBus handles component communication; JSON-Java handles data serialization.

For reliability signals: The RepoPilot analysis rates greenrobot/eventbus as "GO — Healthy across all four use cases," indicating it's well-maintained and suitable for production. For json-java, the repository notes it's in "maintenance phase" [docs/CONTRIBUTING.md:L5], accepting primarily bug fixes and test improvements rather than new features.

Choose based on what your project actually needs to do, not which library is "better."

FOLLOW_UPS:

• What problem are you trying to solve?
• Does your project need event-driven architecture?
• Do you need JSON data interchange capabilities?