ReactiveX / RxJava

RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.

ReactiveX / RxAndroid

RxJava bindings for Android

LFDT-web3j / web3j

Lightweight Java and Android library for integration with Ethereum clients

optimatika / ojAlgo

Pure Java LP, QP and MIP solvers plus fast linear algebra. Zero dependencies, MIT licensed. Mathematical optimization and linear algebra for the JVM.