Tuweni is a set of libraries and other tools to aid development of blockchain and other decentralized software in Java and other JVM languages. It includes a low-level bytes library, serialization and deserialization codecs (e.g. RLP), various cryptography functions and primitives, and lots of other helpful utilities.
To learn how to use Tuweni for low-level libraries, such as bytes, bigints, RLP encoding and so on, follow this tutorial.
To learn more about the networking libraries Tuweni supports, follow along here.
To start using the applications bundled with Tuweni, click here.