feat(McpAsyncClient): Handle ping request

mcp/src/main/java/io/modelcontextprotocol/client/McpAsyncClient.java

@@ -175,6 +175,9 @@ public class McpAsyncClient {
 		// Request Handlers
 		Map<String, RequestHandler<?>> requestHandlers = new HashMap<>();
 
+		// Ping Request Handler
+		requestHandlers.put(McpSchema.METHOD_PING, pingRequestHandler());
+
 		// Roots List Request Handler
 		if (this.clientCapabilities.roots() != null) {
 			requestHandlers.put(McpSchema.METHOD_ROOTS_LIST, rootsListRequestHandler());
@@ -487,6 +490,13 @@ private RequestHandler<McpSchema.ListRootsResult> rootsListRequestHandler() {
 		};
 	}
 
+	// --------------------------
+	// Ping - The receiver MUST respond promptly with an empty response
+	// --------------------------
+	private RequestHandler<Object> pingRequestHandler() {
+		return params -> Mono.just(Map.of());
+	}
+
 	// --------------------------
 	// Sampling
 	// --------------------------

mcp/src/test/java/io/modelcontextprotocol/client/McpAsyncClientResponseHandlerTests.java

@@ -349,4 +349,28 @@ void testSamplingCreateMessageRequestHandlingWithNullHandler() {
 			.hasMessage("Sampling handler must not be null when client capabilities include sampling");
 	}
 
+	@Test
+	void testPingMessageRequestHandling() {
+		MockMcpClientTransport transport = initializationEnabledTransport();
+
+		McpAsyncClient asyncMcpClient = McpClient.async(transport).build();
+
+		// Simulate incoming ping request from server
+		McpSchema.JSONRPCRequest pingRequest = new McpSchema.JSONRPCRequest(McpSchema.JSONRPC_VERSION,
+				McpSchema.METHOD_PING, "ping-id", null);
+		transport.simulateIncomingMessage(pingRequest);
+
+		// Verify response
+		McpSchema.JSONRPCMessage sentMessage = transport.getLastSentMessage();
+		assertThat(sentMessage).isInstanceOf(McpSchema.JSONRPCResponse.class);
+
+		McpSchema.JSONRPCResponse response = (McpSchema.JSONRPCResponse) sentMessage;
+		assertThat(response.id()).isEqualTo("ping-id");
+		assertThat(response.error()).isNull();
+		assertThat(response.result()).isInstanceOf(Map.class);
+		assertThat(((Map<?, ?>) response.result())).isEmpty();
+
+		asyncMcpClient.closeGracefully();
+	}
+
 }