alibaba/spring-ai-alibaba · error · IllegalArgumentException

Configuration cannot be null

Error message

Configuration cannot be null

What it means

FlowGraphBuildingStrategy.validateConfig is a default interface guard that rejects a null FlowGraphConfig before any graph building work begins. It fails fast with IllegalArgumentException rather than a confusing NPE deeper in the builder.

Source

Thrown at spring-ai-alibaba-agent-framework/src/main/java/com/alibaba/cloud/ai/graph/agent/flow/strategy/FlowGraphBuildingStrategy.java:68

	 */
	StateGraph buildGraph(FlowGraphBuilder.FlowGraphConfig config) throws GraphStateException;

	/**
	 * Returns the type identifier for this strategy. This is used for registration and
	 * lookup purposes.
	 * @return the strategy type identifier
	 */
	String getStrategyType();

	/**
	 * Validates that the configuration contains all required parameters for this
	 * strategy.
	 * @param config the configuration to validate
	 * @throws IllegalArgumentException if validation fails
	 */
	default void validateConfig(FlowGraphBuilder.FlowGraphConfig config) {
		if (config == null) {
			throw new IllegalArgumentException("Configuration cannot be null");
		}
		if (config.getName() == null || config.getName().trim().isEmpty()) {
			throw new IllegalArgumentException("Graph name must be provided");
		}
		if (config.getRootAgent() == null) {
			throw new IllegalArgumentException("Root agent must be provided");
		}
		if (config.getKeyStrategyFactory() == null) {
			// Generate a new KeyStrategyFactory based on agent keys
			KeyStrategyFactory generatedFactory = generateKeyStrategyFactory(config);
			config.keyStrategyFactory(generatedFactory);
		}
	}

	/**
	 * Generates a KeyStrategyFactory based on the root agent and sub-agents.
	 * @param config the configuration containing agents
	 * @return the generated KeyStrategyFactory

View on GitHub (pinned to f82da0b50f)

Solutions

1. Construct a FlowGraphConfig via FlowGraphBuilder before calling buildGraph
2. Check your wrapper/helper code for a path that forwards null
3. In tests, assert the builder produces a non-null config

Example fix

// before
strategy.buildGraph(null);
// after
FlowGraphBuilder.FlowGraphConfig config = FlowGraphBuilder.builder()
    .name("my-flow").rootAgent(root).buildConfig();
strategy.buildGraph(config);

Objects.requireNonNull(config, "FlowGraphConfig must not be null");

static FlowGraphConfig requireConfig(FlowGraphBuilder.FlowGraphConfig c) { return java.util.Objects.requireNonNull(c, "config"); }

try { return strategy.buildGraph(config); } catch (IllegalArgumentException e) { throw new FlowBuildException(e.getMessage(), e); }

When it happens

Trigger: Calling buildGraph(null) or FlowGraphBuilder.build() with a config field never initialized (e.g. builder methods not invoked).

Common situations: Programmatic construction where the config object creation was skipped or a null was passed through a helper; mocking in tests returning null.

Related errors

• ${type} requires valid configuration
• Version ID cannot be null
• Conditional flow requires at least one conditional agent map
• Graph name must be provided
• Root agent must be provided

AI-assisted analysis of alibaba/spring-ai-alibaba@f82da0b50f (2026-09-09). Data as JSON: /api/errors/049e64f45906e06d. Report an issue: GitHub.