The Java Stellar SDK is a comprehensive client library for interacting with the Stellar blockchain network, providing both Horizon REST API bindings and Soroban smart contract support. It handles transaction construction, signing, and submission, as well as account management, asset operations, liquidity pools, and decentralized exchange path finding. The library is built on a robust XDR codec layer generated from protocol definitions, with handcrafted decoders that enforce depth limits and size constraints for safe binary parsing. It also includes a SPI-based platform abstraction for Base32/Base64 encoding to support Android deployments, and a sophisticated contract client that manages Soroban transaction lifecycle (simulation, restoration, signing, and submission). The codebase is actively maintained, with a large test suite spanning Java and Kotlin, CI/CD pipelines, and support for the latest Stellar protocol features (CAP-71, CAP-85, SEP-10/45/51/53). While the XDR generation pipeline requires periodic regeneration, the core SDK abstractions are well-isolated and exhibit strong engineering practices such as builder patterns, immutable value objects, and custom Gson deserializers for Horizon response parsing.