MicroBus is inspired by OttoBus, and it has its stronger and weaker points.
Simple events bus (publish–subscribe) implementation based on regular Android
A lightweight and simple event bus for Android.
Type-safe and thread-safe, one-to-many event bus in Java, optimized for speed and low-garbage on Android.
Otto is an event bus designed to decouple different parts of your app while still allowing them to communicate efficiently. Forked from Guava, Otto adds functionality to an already refined event bus as well as specializing it to the Android platform.