fixup

Author: Robby He （贺俊飞）

README.md

@@ -34,7 +34,7 @@ More examples will be added soon.
 
 ## A2A Server
 
-The A2A Java SDK provides a Java server implementation of the [Agent2Agent (A2A) Protocol](https://google-a2a.github.io/A2A). To run your agentic Java application as an A2A server, simply follow the steps below.
+The A2A Java SDK provides a Java server implementation of the [Agent2Agent (A2A) Protocol](https://a2a-protocol.org/). To run your agentic Java application as an A2A server, simply follow the steps below.
 
 - [Add an A2A Java SDK Server Maven dependency to your project](#1-add-an-a2a-java-sdk-server-maven-dependency-to-your-project)
 - [Add a class that creates an A2A Agent Card](#2-add-a-class-that-creates-an-a2a-agent-card)
@@ -266,7 +266,7 @@ a2a.executor.keep-alive-seconds=60
 
 ## A2A Client
 
-The A2A Java SDK provides a Java client implementation of the [Agent2Agent (A2A) Protocol](https://google-a2a.github.io/A2A), allowing communication with A2A servers. The Java client implementation supports the following transports:
+The A2A Java SDK provides a Java client implementation of the [Agent2Agent (A2A) Protocol](https://a2a-protocol.org/), allowing communication with A2A servers. The Java client implementation supports the following transports:
 
 * JSON-RPC 2.0
 * gRPC