Adjust packages in mcp-json-jackson2 to jackson2 packages

deprecate classes for removal in `io.modelcontextprotocol.json.jackson`/`io.modelcontextprotocol.json.schema.jackson`
and copy them to `io.modelcontextprotocol.json.jackson2`/`io.modelcontextprotocol.json.schema.jackson2` in non-deprecated form.

Author: filiphr

mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson/JacksonMcpJsonMapper.java

@@ -14,7 +14,12 @@
 /**
  * Jackson-based implementation of JsonMapper. Wraps a Jackson ObjectMapper but keeps the
  * SDK decoupled from Jackson at the API level.
+ *
+ * @deprecated since 18.0.0, use
+ * {@link io.modelcontextprotocol.json.jackson2.JacksonMcpJsonMapper} instead. Will be
+ * removed in 19.0.0
  */
+@Deprecated(forRemoval = true, since = "18.0.0")
 public final class JacksonMcpJsonMapper implements McpJsonMapper {
 
 	private final ObjectMapper objectMapper;

mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson/JacksonMcpJsonMapperSupplier.java

@@ -13,7 +13,12 @@
  * <p>
  * This implementation provides a {@link McpJsonMapper} backed by a Jackson
  * {@link com.fasterxml.jackson.databind.ObjectMapper}.
+ *
+ * @deprecated since 18.0.0, use
+ * {@link io.modelcontextprotocol.json.jackson2.JacksonMcpJsonMapperSupplier} instead.
+ * Will be removed in 19.0.0.
  */
+@Deprecated(forRemoval = true, since = "18.0.0")
 public class JacksonMcpJsonMapperSupplier implements McpJsonMapperSupplier {
 
 	/**

mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson2/JacksonMcpJsonMapper.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2026 - 2026 the original author or authors.
+ */
+
+package io.modelcontextprotocol.json.jackson2;
+
+import java.io.IOException;
+
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import io.modelcontextprotocol.json.McpJsonMapper;
+import io.modelcontextprotocol.json.TypeRef;
+
+/**
+ * Jackson-based implementation of JsonMapper. Wraps a Jackson ObjectMapper but keeps the
+ * SDK decoupled from Jackson at the API level.
+ */
+public final class JacksonMcpJsonMapper implements McpJsonMapper {
+
+	private final ObjectMapper objectMapper;
+
+	/**
+	 * Constructs a new JacksonMcpJsonMapper instance with the given ObjectMapper.
+	 * @param objectMapper the ObjectMapper to be used for JSON serialization and
+	 * deserialization. Must not be null.
+	 * @throws IllegalArgumentException if the provided ObjectMapper is null.
+	 */
+	public JacksonMcpJsonMapper(ObjectMapper objectMapper) {
+		if (objectMapper == null) {
+			throw new IllegalArgumentException("ObjectMapper must not be null");
+		}
+		this.objectMapper = objectMapper;
+	}
+
+	/**
+	 * Returns the underlying Jackson {@link ObjectMapper} used for JSON serialization and
+	 * deserialization.
+	 * @return the ObjectMapper instance
+	 */
+	public ObjectMapper getObjectMapper() {
+		return objectMapper;
+	}
+
+	@Override
+	public <T> T readValue(String content, Class<T> type) throws IOException {
+		return objectMapper.readValue(content, type);
+	}
+
+	@Override
+	public <T> T readValue(byte[] content, Class<T> type) throws IOException {
+		return objectMapper.readValue(content, type);
+	}
+
+	@Override
+	public <T> T readValue(String content, TypeRef<T> type) throws IOException {
+		JavaType javaType = objectMapper.getTypeFactory().constructType(type.getType());
+		return objectMapper.readValue(content, javaType);
+	}
+
+	@Override
+	public <T> T readValue(byte[] content, TypeRef<T> type) throws IOException {
+		JavaType javaType = objectMapper.getTypeFactory().constructType(type.getType());
+		return objectMapper.readValue(content, javaType);
+	}
+
+	@Override
+	public <T> T convertValue(Object fromValue, Class<T> type) {
+		return objectMapper.convertValue(fromValue, type);
+	}
+
+	@Override
+	public <T> T convertValue(Object fromValue, TypeRef<T> type) {
+		JavaType javaType = objectMapper.getTypeFactory().constructType(type.getType());
+		return objectMapper.convertValue(fromValue, javaType);
+	}
+
+	@Override
+	public String writeValueAsString(Object value) throws IOException {
+		return objectMapper.writeValueAsString(value);
+	}
+
+	@Override
+	public byte[] writeValueAsBytes(Object value) throws IOException {
+		return objectMapper.writeValueAsBytes(value);
+	}
+
+}

mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson2/JacksonMcpJsonMapperSupplier.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2026 - 2026 the original author or authors.
+ */
+
+package io.modelcontextprotocol.json.jackson2;
+
+import io.modelcontextprotocol.json.McpJsonMapper;
+import io.modelcontextprotocol.json.McpJsonMapperSupplier;
+
+/**
+ * A supplier of {@link McpJsonMapper} instances that uses the Jackson library for JSON
+ * serialization and deserialization.
+ * <p>
+ * This implementation provides a {@link McpJsonMapper} backed by a Jackson
+ * {@link com.fasterxml.jackson.databind.ObjectMapper}.
+ */
+public class JacksonMcpJsonMapperSupplier implements McpJsonMapperSupplier {
+
+	/**
+	 * Returns a new instance of {@link McpJsonMapper} that uses the Jackson library for
+	 * JSON serialization and deserialization.
+	 * <p>
+	 * The returned {@link McpJsonMapper} is backed by a new instance of
+	 * {@link com.fasterxml.jackson.databind.ObjectMapper}.
+	 * @return a new {@link McpJsonMapper} instance
+	 */
+	@Override
+	public McpJsonMapper get() {
+		return new JacksonMcpJsonMapper(new com.fasterxml.jackson.databind.ObjectMapper());
+	}
+
+}

mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson/DefaultJsonSchemaValidator.java

@@ -24,7 +24,11 @@
  * NetworkNT JSON Schema Validator library for validation.
  *
  * @author Christian Tzolov
+ * @deprecated since 18.0.0, use
+ * {@link io.modelcontextprotocol.json.schema.jackson2.DefaultJsonSchemaValidator}
+ * instead. Will be removed in 19.0.0.
  */
+@Deprecated(forRemoval = true, since = "18.0.0")
 public class DefaultJsonSchemaValidator implements JsonSchemaValidator {
 
 	private static final Logger logger = LoggerFactory.getLogger(DefaultJsonSchemaValidator.class);

mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson/JacksonJsonSchemaValidatorSupplier.java

@@ -13,6 +13,9 @@
  *
  * @see JsonSchemaValidatorSupplier
  * @see JsonSchemaValidator
+ * @deprecated since 18.0.0, use
+ * {@link io.modelcontextprotocol.json.schema.jackson2.JacksonJsonSchemaValidatorSupplier}
+ * instead. Will be removed in 19.0.0.
  */
 public class JacksonJsonSchemaValidatorSupplier implements JsonSchemaValidatorSupplier {
 

mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson2/DefaultJsonSchemaValidator.java

@@ -0,0 +1,163 @@
+/*
+ * Copyright 2026-2026 the original author or authors.
+ */
+package io.modelcontextprotocol.json.schema.jackson2;
+
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.networknt.schema.Error;
+import com.networknt.schema.Schema;
+import com.networknt.schema.SchemaRegistry;
+import com.networknt.schema.dialect.Dialects;
+
+import io.modelcontextprotocol.json.schema.JsonSchemaValidator;
+
+/**
+ * Default implementation of the {@link JsonSchemaValidator} interface. This class
+ * provides methods to validate structured content against a JSON schema. It uses the
+ * NetworkNT JSON Schema Validator library for validation.
+ *
+ * @author Christian Tzolov
+ */
+public class DefaultJsonSchemaValidator implements JsonSchemaValidator {
+
+	private static final Logger logger = LoggerFactory.getLogger(DefaultJsonSchemaValidator.class);
+
+	private final ObjectMapper objectMapper;
+
+	private final SchemaRegistry schemaFactory;
+
+	// TODO: Implement a strategy to purge the cache (TTL, size limit, etc.)
+	private final ConcurrentHashMap<String, Schema> schemaCache;
+
+	public DefaultJsonSchemaValidator() {
+		this(new ObjectMapper());
+	}
+
+	public DefaultJsonSchemaValidator(ObjectMapper objectMapper) {
+		this.objectMapper = objectMapper;
+		this.schemaFactory = SchemaRegistry.withDialect(Dialects.getDraft202012());
+		this.schemaCache = new ConcurrentHashMap<>();
+	}
+
+	@Override
+	public ValidationResponse validate(Map<String, Object> schema, Object structuredContent) {
+
+		if (schema == null) {
+			throw new IllegalArgumentException("Schema must not be null");
+		}
+		if (structuredContent == null) {
+			throw new IllegalArgumentException("Structured content must not be null");
+		}
+
+		try {
+
+			JsonNode jsonStructuredOutput = (structuredContent instanceof String)
+					? this.objectMapper.readTree((String) structuredContent)
+					: this.objectMapper.valueToTree(structuredContent);
+
+			List<Error> validationResult = this.getOrCreateJsonSchema(schema).validate(jsonStructuredOutput);
+
+			// Check if validation passed
+			if (!validationResult.isEmpty()) {
+				return ValidationResponse
+					.asInvalid("Validation failed: structuredContent does not match tool outputSchema. "
+							+ "Validation errors: " + validationResult);
+			}
+
+			return ValidationResponse.asValid(jsonStructuredOutput.toString());
+
+		}
+		catch (JsonProcessingException e) {
+			logger.error("Failed to validate CallToolResult: Error parsing schema: {}", e);
+			return ValidationResponse.asInvalid("Error parsing tool JSON Schema: " + e.getMessage());
+		}
+		catch (Exception e) {
+			logger.error("Failed to validate CallToolResult: Unexpected error: {}", e);
+			return ValidationResponse.asInvalid("Unexpected validation error: " + e.getMessage());
+		}
+	}
+
+	/**
+	 * Gets a cached Schema or creates and caches a new one.
+	 * @param schema the schema map to convert
+	 * @return the compiled Schema
+	 * @throws JsonProcessingException if schema processing fails
+	 */
+	private Schema getOrCreateJsonSchema(Map<String, Object> schema) throws JsonProcessingException {
+		// Generate cache key based on schema content
+		String cacheKey = this.generateCacheKey(schema);
+
+		// Try to get from cache first
+		Schema cachedSchema = this.schemaCache.get(cacheKey);
+		if (cachedSchema != null) {
+			return cachedSchema;
+		}
+
+		// Create new schema if not in cache
+		Schema newSchema = this.createJsonSchema(schema);
+
+		// Cache the schema
+		Schema existingSchema = this.schemaCache.putIfAbsent(cacheKey, newSchema);
+		return existingSchema != null ? existingSchema : newSchema;
+	}
+
+	/**
+	 * Creates a new Schema from the given schema map.
+	 * @param schema the schema map
+	 * @return the compiled Schema
+	 * @throws JsonProcessingException if schema processing fails
+	 */
+	private Schema createJsonSchema(Map<String, Object> schema) throws JsonProcessingException {
+		// Convert schema map directly to JsonNode (more efficient than string
+		// serialization)
+		JsonNode schemaNode = this.objectMapper.valueToTree(schema);
+
+		// Handle case where ObjectMapper might return null (e.g., in mocked scenarios)
+		if (schemaNode == null) {
+			throw new JsonProcessingException("Failed to convert schema to JsonNode") {
+			};
+		}
+
+		return this.schemaFactory.getSchema(schemaNode);
+	}
+
+	/**
+	 * Generates a cache key for the given schema map.
+	 * @param schema the schema map
+	 * @return a cache key string
+	 */
+	protected String generateCacheKey(Map<String, Object> schema) {
+		if (schema.containsKey("$id")) {
+			// Use the (optional) "$id" field as the cache key if present
+			return "" + schema.get("$id");
+		}
+		// Fall back to schema's hash code as a simple cache key
+		// For more sophisticated caching, could use content-based hashing
+		return String.valueOf(schema.hashCode());
+	}
+
+	/**
+	 * Clears the schema cache. Useful for testing or memory management.
+	 */
+	public void clearCache() {
+		this.schemaCache.clear();
+	}
+
+	/**
+	 * Returns the current size of the schema cache.
+	 * @return the number of cached schemas
+	 */
+	public int getCacheSize() {
+		return this.schemaCache.size();
+	}
+
+}

mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson2/JacksonJsonSchemaValidatorSupplier.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2026 - 2026 the original author or authors.
+ */
+
+package io.modelcontextprotocol.json.schema.jackson2;
+
+import io.modelcontextprotocol.json.schema.JsonSchemaValidator;
+import io.modelcontextprotocol.json.schema.JsonSchemaValidatorSupplier;
+
+/**
+ * A concrete implementation of {@link JsonSchemaValidatorSupplier} that provides a
+ * {@link JsonSchemaValidator} instance based on the Jackson library.
+ *
+ * @see JsonSchemaValidatorSupplier
+ * @see JsonSchemaValidator
+ */
+public class JacksonJsonSchemaValidatorSupplier implements JsonSchemaValidatorSupplier {
+
+	/**
+	 * Returns a new instance of {@link JsonSchemaValidator} that uses the Jackson library
+	 * for JSON schema validation.
+	 * @return A {@link JsonSchemaValidator} instance.
+	 */
+	@Override
+	public JsonSchemaValidator get() {
+		return new DefaultJsonSchemaValidator();
+	}
+
+}

mcp-json-jackson2/src/main/resources/META-INF/services/io.modelcontextprotocol.json.McpJsonMapperSupplier

@@ -1 +1 @@
-io.modelcontextprotocol.json.jackson.JacksonMcpJsonMapperSupplier
+io.modelcontextprotocol.json.jackson2.JacksonMcpJsonMapperSupplier

mcp-json-jackson2/src/main/resources/META-INF/services/io.modelcontextprotocol.json.schema.JsonSchemaValidatorSupplier

@@ -1 +1 @@
-io.modelcontextprotocol.json.schema.jackson.JacksonJsonSchemaValidatorSupplier
+io.modelcontextprotocol.json.schema.jackson2.JacksonJsonSchemaValidatorSupplier