spring-projects/spring-ai · error · IllegalStateException

Failed to invoke createIndex() method

Error message

Failed to invoke createIndex() method

What it means

This is the first branch of the same reflective index creation: when createIndex(IndexDefinition) is looked up successfully on IndexOperations but invoking it throws a ReflectiveOperationException, the Mongo chat memory auto-configuration wraps it in an IllegalStateException with this message. The real failure is in the chained cause.

Source

Thrown at auto-configurations/models/chat/memory/repository/spring-ai-autoconfigure-model-chat-memory-repository-mongodb/src/main/java/org/springframework/ai/model/chat/memory/repository/mongo/autoconfigure/MongoChatMemoryIndexCreatorAutoConfiguration.java:135

		catch (NoSuchMethodException createIndexNotFound) {
			// Fall back to old API (Spring Data MongoDB 4.2.x - 4.4.x)
			try {
				Method method = IndexOperations.class.getMethod("ensureIndex", IndexDefinition.class);
				method.invoke(indexOps, index);
				logger.debug("Created index using ensureIndex() method");
			}
			catch (NoSuchMethodException ensureIndexNotFound) {
				throw new IllegalStateException(
						"Neither createIndex() nor ensureIndex() method found on IndexOperations. "
								+ "This may indicate an unsupported Spring Data MongoDB version.",
						ensureIndexNotFound);
			}
			catch (ReflectiveOperationException ex) {
				throw new IllegalStateException("Failed to invoke ensureIndex() method", ex);
			}
		}
		catch (ReflectiveOperationException ex) {
			throw new IllegalStateException("Failed to invoke createIndex() method", ex);
		}
	}

}

View on GitHub (pinned to 98a7beda4f)

Solutions

1. Read the wrapped cause exception to find the actual MongoDB error.
2. Confirm the index definition (field, direction, TTL options) is valid for your server version.
3. Ensure the database user can create indexes on the chat memory collection.
4. Align spring-data-mongodb and mongodb-driver versions with the Spring AI BOM.

Example fix

// before
catch (ReflectiveOperationException ex) { throw new IllegalStateException("Failed to invoke createIndex() method", ex); } // cause hidden
// after
catch (ReflectiveOperationException ex) { logger.error("createIndex failed: {}", ex.getCause()); throw new IllegalStateException("Failed to invoke createIndex() method", ex); }

// pre-check: collection is writable and driver/server compatible
mongoTemplate.collectionExists("ai_chat_memory");

When it happens

Trigger: createIndexSafely resolves Method createIndex(IndexDefinition) but method.invoke(indexOps, index) throws IllegalAccessException or InvocationTargetException while called from createMainIndex or createOrUpdateTtlIndex at startup.

Common situations: MongoDB rejecting the index specification (bad keys, unsupported options); insufficient write permissions on the collection; driver/server version mismatch on index options like partialFilterExpression or expireAfterSeconds.

Related errors

• Failed to invoke ensureIndex() method
• Neither createIndex() nor ensureIndex() method found on Inde
• Required no-arg constructor not found in
• instantiation failed
• Method must not be null

AI-assisted analysis of spring-projects/spring-ai@98a7beda4f (2026-09-11). Data as JSON: /api/errors/3fe784243fcb67c8. Report an issue: GitHub.