BAEL-9308: Java SDK for MCP

Author: brokenhardisk

java-mcp/src/main/java/mcp/LoggingTool.java

@@ -11,11 +11,9 @@ public class LoggingTool {
 
     public static McpServerFeatures.SyncToolSpecification logPromptTool() {
         McpSchema.JsonSchema inputSchema = new McpSchema.JsonSchema("object", Map.of("prompt", String.class), List.of("prompt"), false, null, null);
-        Map<String, Object> outputSchema = new HashMap<>();
-        outputSchema.put("logged", "string");
 
         return new McpServerFeatures.SyncToolSpecification(
-            new McpSchema.Tool("logPrompt", "Log Prompt", "Logs a provided prompt", inputSchema, outputSchema, null, null), (exchange, args) -> {
+            new McpSchema.Tool("logPrompt", "Log Prompt", "Logs a provided prompt", inputSchema, null, null, null), (exchange, args) -> {
             String prompt = (String) args.get("prompt");
             return McpSchema.CallToolResult.builder()
                 .content(List.of(new McpSchema.TextContent("Input Prompt: " + prompt)))

java-mcp/src/main/java/mcp/McpClientApp2.java

@@ -0,0 +1,51 @@
+package mcp;
+
+import java.io.IOException;
+import java.util.Map;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import io.modelcontextprotocol.client.McpClient;
+import io.modelcontextprotocol.client.McpSyncClient;
+import io.modelcontextprotocol.client.transport.ServerParameters;
+import io.modelcontextprotocol.client.transport.StdioClientTransport;
+import io.modelcontextprotocol.json.jackson.JacksonMcpJsonMapper;
+import io.modelcontextprotocol.spec.McpClientTransport;
+import io.modelcontextprotocol.spec.McpSchema.CallToolRequest;
+import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
+import io.modelcontextprotocol.spec.McpSchema.ListToolsResult;
+
+
+public class McpClientApp2 {
+
+    private static final Logger log = LoggerFactory.getLogger(McpClientApp2.class);
+
+    public static void main(String[] args) {
+        String jarPath = new java.io.File("java-mcp/target/java-mcp-1.0.0-SNAPSHOT.jar").getAbsolutePath();
+        ServerParameters params = ServerParameters.builder("java")
+            .args("-jar", jarPath)
+            .build();
+
+        JacksonMcpJsonMapper jsonMapper = new JacksonMcpJsonMapper(new ObjectMapper());
+        McpClientTransport transport = new StdioClientTransport(params, jsonMapper);
+
+        McpSyncClient client = McpClient.sync(transport)
+            .build();
+
+        client.initialize();
+
+        ListToolsResult tools = client.listTools();
+        McpClientApp2.log.info("Tools exposed by the server:");
+        tools.tools()
+            .forEach(tool -> System.out.println(" - " + tool.name()));
+
+        McpClientApp2.log.info("\nCalling 'logPrompt' tool...");
+        CallToolResult result = client.callTool(new CallToolRequest("logPrompt", Map.of("prompt", "Hello from MCP client!")));
+        McpClientApp2.log.info("Result: " + result.content());
+
+        client.closeGracefully();
+    }
+}

java-mcp/src/main/resources/logback.xml

@@ -0,0 +1,12 @@
+<configuration>
+    <appender name="STDERR" class="ch.qos.logback.core.ConsoleAppender">
+        <target>System.err</target>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="info">
+        <appender-ref ref="STDERR"/>
+    </root>
+</configuration>

java-mcp/src/test/java/mcp/McpClientAppServerUnitTest.java

@@ -38,7 +38,7 @@ void whenLogPromptToolCalled_thenReturnsResult() {
     }
 
     @Test
-    void whenCalledViaClient_thenReturnsLoggedResult() throws Exception {
+    void whenCalledViaClient_thenReturnsLoggedResult() {
         McpSchema.CallToolRequest request = new McpSchema.CallToolRequest("echo", Map.of("message", "Client-server test message"));
         McpSchema.CallToolResult result = client.callTool(request);