A2A Java SDK - Extras

This directory contains additions to what is provided by the default SDK implementations.

Please see the README's of each child directory for more details.

HTTP Client

http-client-vertx - Vert.x WebClient-based implementation of A2AHttpClient for reactive, high-performance HTTP communication. Replaces the default JDK HttpClient with a non-blocking, event-loop based client. Uses SPI for automatic discovery - simply add this library as a dependency to use it. Recommended for reactive applications, Quarkus, and high-throughput scenarios.

Storage & Persistence

task-store-database-jpa - Replaces the default InMemoryTaskStore with a TaskStore backed by a RDBMS. It uses JPA to interact with the RDBMS, providing persistence across application restarts and shared state in multi-instance deployments.

push-notification-config-store-database-jpa - Replaces the default InMemoryPushNotificationConfigStore with a PushNotificationConfigStore backed by a RDBMS. It uses JPA to interact with the RDBMS, ensuring push notification subscriptions survive restarts.

Distributed Systems

queue-manager-replicated - Replaces the default InMemoryQueueManager with a QueueManager supporting replication to other A2A servers implementing the same agent. Required for multi-instance deployments. You can write your own ReplicationStrategy, or use the provided MicroProfile Reactive Messaging implementation with Apache Kafka, Pulsar, or AMQP.