...The SDK provides both synchronous clients and a high-performance asynchronous stack built on event-driven HTTP, enabling reactive pipelines and high-throughput services. Models are immutable and builders are pervasive, leading to safer code and clearer intent. Credential providers, region resolution, retries, and paginators are redesigned with extensibility in mind, and integrations are available for common observability and HTTP client choices. For teams starting new Java projects on AWS, v2 is the default choice due to its modularity, improved ergonomics, and better runtime characteristics.