alibaba/Sentinel · error · IllegalArgumentException

Invalid object: null

Error message

Invalid object: null

What it means

Thrown by the static factory ParamFlowItem.newItem(object, count) when object is null. A ParamFlowItem stores the hot-parameter threshold as object.toString() plus its class type, so a null parameter has neither representation; the factory rejects it before creating a meaningless item.

Source

Thrown at sentinel-extension/sentinel-parameter-flow-control/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/param/ParamFlowItem.java:41

 * @since 0.2.0
 */
public class ParamFlowItem {

    private String object;
    private Integer count;
    private String classType;

    public ParamFlowItem() {}

    public ParamFlowItem(String object, Integer count, String classType) {
        this.object = object;
        this.count = count;
        this.classType = classType;
    }

    public static <T> ParamFlowItem newItem(T object, Integer count) {
        if (object == null) {
            throw new IllegalArgumentException("Invalid object: null");
        }
        return new ParamFlowItem(object.toString(), count, object.getClass().getName());
    }

    public String getObject() {
        return object;
    }

    public ParamFlowItem setObject(String object) {
        this.object = object;
        return this;
    }

    public Integer getCount() {
        return count;
    }

    public ParamFlowItem setCount(Integer count) {

View on GitHub (pinned to a3f40ba8e9)

Solutions

1. Ensure the parameter object is non-null before calling newItem; skip or default the entry when the source value is null.
2. If the value comes from a map, check containsKey/get != null first and log which key was missing.
3. Note newItem uses object.toString() and getClass().getName() — use a primitive wrapper/String or a type with a meaningful toString().

Example fix

// before
ParamFlowItem item = ParamFlowItem.newItem(paramMap.get("userId"), 10); // null when key absent

// after
Object userId = paramMap.get("userId");
if (userId == null) { throw new IllegalArgumentException("paramMap missing userId"); }
ParamFlowItem item = ParamFlowItem.newItem(userId, 10);

public static ParamFlowItem safeNewItem(Object param, Integer count) {
    if (param == null) {
        throw new IllegalArgumentException("hot parameter must not be null");
    }
    return ParamFlowItem.newItem(param, count);
}

try {
    items.add(ParamFlowItem.newItem(param, count));
} catch (IllegalArgumentException e) {
    if (e.getMessage() != null && e.getMessage().contains("Invalid object")) {
        log.warn("skipping hot-param rule for null parameter");
        return; // or apply a default
    }
    throw e;
}

When it happens

Trigger: ParamFlowItem.newItem(null, count) — usually a parameter value that came back null from a map lookup, request attribute, or configuration (e.g. paramMap.get("user") returning null for an absent key) and is forwarded to newItem without a null check.

Common situations: Building ParameterFlowRule entities programmatically from user input or config maps where a key may be absent; deserializing rules where a field was optional; unit tests passing null accidentally.

Related errors

• Config encoder cannot be null
• File can't be null or a directory
• charset can't be null
• ${filePath} file size=${fileSize}, is bigger than bufSize=${
• Bad file

AI-assisted analysis of alibaba/Sentinel@a3f40ba8e9 (2026-08-14). Data as JSON: /api/errors/2cb2f6c796e8cb83. Report an issue: GitHub.