EventBus VS otto

Nope, it's not: https://github.com/greenrobot/EventBus

Project: EventBus (EventBus is a publish/subscribe event bus optimized for Android.) Copyright (C) 2012-2016 Markus Junginger, greenrobot. License (Apache License Version 2.0) https://github.com/greenrobot/EventBus/blob/master/LICENSE

I am involved in the development of Android application which is a rather "thick" mobile client for a Web service. It heavily communicates with the server but also has a lot of inner logic too. So, I decided to use some features of Google Guava library to simplify development process. Here is a list of features I'm very interested in: immutable collections, base utils, collection extensions, functional programming sugar and idioms (common.collect and common.base), primitives utilities (common.primitives), hashing utilities (common.hash), concurrent utils (futures and AsyncFunction). Things I don't want to use in Android: common.cache (see question below), common.eventbus (we have better Android specific libs for this, such as Otto), common.io (we can use okio for Android now).

1. I'm happy to see that EventBus has made this change. Let's hope the long overdue AndroidX migration (we're three years into AndroidX, folks) follows close on its heels.

2. Event buses are really, really bad. (At least, this kind of event bus is) The Android community has some battle scars on this, so I'll drop a little history for the broader audience here.

Event buses were an architectural fad that were briefly explored to address the challenges of communicating in the immature application architectures of the era. The maintenance lifetime of Otto, a competing event bus, is a good reference point for when they might have been considered reasonable practice: 2012 through 2015: https://github.com/square/otto/tags

This tool was abandoned by leading edge shops when they saw how rapidly it could make a complete hash of any thoughtfully laid out architecture. Connections made in an EventBus based application tend to be many-to-many, without the sender of an event having a direct reference to its recipient or vice versa. This is incredibly irritating to debug, and breeds communication patterns that are challenging even in a disciplined codebase. In an _undisciplined_ codebase they can be breathtakingly byzantine, even in small scale development.

Instead of using this, many leading edge shops started switching to RxJava at around 2016. RxJava is a powerful tool with sharp edges and a steep learning curve, but the need was so imminent and the failings of the existing EventBus-style tools so clear that it caught on. Indeed, while Google understandably felt it RxJava was too complex to recommend as an introductory tool, their first party LiveData tool released a few years later was essentially RxJava with the edges sanded off.

Of course, we're not even further down the road than that. Kotlin coroutines presents its own paradigm shift to contend with, but it's a clear step up from all the other solutions, and has Google's blessing as well. There's not much reason to start new development on top of anything except coroutines.

So where does that leave EventBus?

EventBus is at this point about as legacy as you can get without going all the way back to AsyncTask. Anytime I'm doing a code audit and see this dependency, red flags immediately go up: not only is it a sign that this code is far behind the times, but it's also a flag that I'm going to find some truly unfortunate and problematic design decisions.

People need what they need, and it's of course good to see critical dependencies for legacy applications get upgrades. But I can't recommend strongly enough to avoid this tool.