alibaba/spring-ai-alibaba · warning · IllegalStateException

Constructor did not produce a Map instance:

Error message

Constructor did not produce a Map instance: 

What it means

SerializationUtils.deepCopyMap attempts to deep-copy a Map by reflectively instantiating the original map's concrete class with a no-arg constructor. If the created instance is not a Map (or reflection fails), it falls back to HashMap after logging; the IllegalStateException is thrown when the no-arg constructor somehow produced a non-Map object — an invariant that should be impossible for a Map subclass.

Source

Thrown at spring-ai-alibaba-graph-core/src/main/java/com/alibaba/cloud/ai/graph/utils/SerializationUtils.java:71

	 * @param original the original Map object
	 * @return the deep copied Map object, returns null if the original object is null
	 */
	@SuppressWarnings("unchecked")
	public static Map<String, Object> deepCopyMap(Map<String, Object> original) {
		if (original == null) {
			return null;
		}

		// Preserve the original Map type if it's not a standard Map implementation
		// This handles cases like fastjson2's JSONObject (which extends LinkedHashMap)
		Map<String, Object> copy;
		try {
			// Try to create an instance of the same class
			var constructor = original.getClass().getDeclaredConstructor();
			constructor.setAccessible(true);  // Handle non-public constructors
			Object instance = constructor.newInstance();
			if (!(instance instanceof Map)) {
				throw new IllegalStateException("Constructor did not produce a Map instance: " + original.getClass().getName());
			}
			copy = (Map<String, Object>) instance;
			log.debug("Successfully preserved Map type: {}", original.getClass().getName());
		} catch (Exception e) {
			// If instantiation fails, fall back to HashMap
			log.debug("Could not preserve Map type {}, falling back to HashMap: {}", 
				original.getClass().getName(), e.getMessage());
			copy = new HashMap<>();
		}
		
		for (Map.Entry<String, Object> entry : original.entrySet()) {
			copy.put(entry.getKey(), deepCopyValue(entry.getValue()));
		}
		return copy;
	}

	/**
	 * Recursively deep copy values of any type

View on GitHub (pinned to f82da0b50f)

Solutions

1. Use standard Map implementations (HashMap, LinkedHashMap, TreeMap) in graph state.
2. Remove the custom Map subclass or give it a public no-arg constructor that returns a proper Map.
3. Wrap state values in plain collections before adding them to OverAllState.

Example fix

// before
state.put("data", new MyCustomMap<String,Object>(delegate));
// after
state.put("data", new LinkedHashMap<>(myCustomMap));

Object v = state.get("data");
if (!(v instanceof HashMap || v instanceof LinkedHashMap || v instanceof TreeMap)) {
  // normalize before adding to graph state
  v = new LinkedHashMap<>((Map<String,Object>) v);
}

boolean isCopySafeMap(Object v) {
  return v instanceof Map && v.getClass().getDeclaredConstructors().length > 0
      && v instanceof HashMap || v instanceof LinkedHashMap || v instanceof TreeMap;
}

try {
  Map<String,Object> copy = SerializationUtils.deepCopy(state.data());
} catch (IllegalStateException e) {
  log.warn("deepCopy failed: {}", e.getMessage());
  Map<String,Object> copy = new HashMap<>(state.data());
}

When it happens

Trigger: Calling deepCopy (via deepCopyValue) on a state Map whose concrete class has a no-arg constructor returning a non-Map instance, or whose reflection-based instantiation path misbehaves; mainly reachable when custom Map implementations are placed into graph state.

Common situations: Users put exotic Map subclasses (e.g. wrapper/delegating maps, immutable builders) into OverAllState; classpath anomalies or bytecode tricks cause the check to fire.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• Could not find executeAgent method in AgentToolExecutor clas
• Cannot instantiate array type: {}
• Unsupported array type representation: {}
• Utility class
• Utility class

AI-assisted analysis of alibaba/spring-ai-alibaba@f82da0b50f (2026-09-09). Data as JSON: /api/errors/d6e1e558a7a34d4a. Report an issue: GitHub.