streamsupport is a backport of the Java 8 java.util.function (functional interfaces) and java.util.stream (streams) API for Java 6 / 7 and Android developers

web3j is a lightweight Java library for integration with Ethereum clients

Ethereum Application Binary Interface (ABI) for working with smart contracts

streamsupport-cfuture is a backport of the Java 8 CompletableFuture API with the current Java 9 (JEP 266) enhancements for Java 6 to 8 and Android developers

Java for Rust

The Protelis language interpreter

streamsupport-atomic is a backport of the java.util.concurrent.atomic classes added in Java 8 (Double/Long Accumulator/Adder) for Java 6 / 7 and Android developers

Stream Feeds Java Client for backend and android integrations

Guava cache supplier extension to memoize exceptions, fallback, expiration control.

Extlibj

Nightjar