diff --git a/mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java b/mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
index 07a9f15..ef69539 100644
--- a/mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
+++ b/mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
@@ -6,6 +6,7 @@ package io.modelcontextprotocol.server;
 
 import java.time.Duration;
 import java.util.HashMap;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -403,7 +404,7 @@ public class McpAsyncServer {
 			// Initialize request handlers for standard MCP methods
 
 			// Ping MUST respond with an empty data, but not NULL response.
-			requestHandlers.put(McpSchema.METHOD_PING, (exchange, params) -> Mono.just(""));
+			requestHandlers.put(McpSchema.METHOD_PING, (exchange, params) -> Mono.just(Map.of()));
 
 			// Add tools API handlers if the tool capability is enabled
 			if (this.serverCapabilities.tools() != null) {
@@ -926,7 +927,7 @@ public class McpAsyncServer {
 			requestHandlers.put(McpSchema.METHOD_INITIALIZE, asyncInitializeRequestHandler());
 
 			// Ping MUST respond with an empty data, but not NULL response.
-			requestHandlers.put(McpSchema.METHOD_PING, (params) -> Mono.just(""));
+			requestHandlers.put(McpSchema.METHOD_PING, (params) -> Mono.just(Map.of()));
 
 			// Add tools API handlers if the tool capability is enabled
 			if (this.serverCapabilities.tools() != null) {