This sample shows how to invoke an A2A-compliant HTTP endpoint from the Google ADK runtime using the reusable google-adk-a2a module. It wires a RemoteA2AAgent to the production JdkA2AHttpClient, so you can exercise a running service (for example the a2a_server sample).

1. Start the a2a_server sample (or point to any other A2A-compliant endpoint):

   cd google_adk
   GOOGLE_API_KEY=your_api_key \
     ./mvnw -f examples/a2a_server/pom.xml quarkus:dev

cd google_adk
./mvnw -f examples/a2a_basic/pom.xml exec:java \
  -Dexec.args="http://localhost:9090"

You should see the client log each turn, including the remote agent response (e.g. 4 is not a prime number.).

To run the client in the background and capture logs:

nohup env GOOGLE_GENAI_USE_VERTEXAI=FALSE \
  GOOGLE_API_KEY=your_api_key \
  ./mvnw -f examples/a2a_basic/pom.xml exec:java \
  -Dexec.args="http://localhost:9090" \
  > /tmp/a2a_basic.log 2>&1 & echo $!

Tail /tmp/a2a_basic.log to inspect the conversation.

• A2AAgent.java – builds a root agent with a local dice-rolling tool and a remote prime-checking sub-agent.
• A2AAgentRun.java – minimal driver that executes a single SendMessage turn to demonstrate the remote call.
• pom.xml – standalone Maven configuration for building and running the sample.