flowable/flowable-engine · error · FlowableIllegalArgumentException

Task name is null

Error message

Task name is null

What it means

Flowable throws this FlowableIllegalArgumentException when TaskQuery.taskName(null) is called. The name filter requires a concrete value for the SQL equality predicate, so null is rejected at build time. This is an argument-validation failure, not a query-execution failure.

Solutions

1. Null-check the name and omit the taskName filter when absent.
2. Provide a default task name value in configuration if the filter is required.
3. Validate the request parameter at the boundary before building the query.
4. If partial matching was intended, use taskNameLike with a validated non-null pattern.

Example fix

// before
query.taskName(filter.getName()); // throws when name is null
// after
if (filter.getName() != null) {
    query.taskName(filter.getName());
}

if (name != null) {
    query.taskName(name);
}

boolean isNotBlank(String s) { return s != null && !s.trim().isEmpty(); }

try {
    query.taskName(name);
} catch (FlowableIllegalArgumentException e) {
    if (e.getMessage().equals("Task name is null")) {
        throw new BadRequestException("task name filter must not be null", e);
    }
    throw e;
}

When it happens

Trigger: Calling createTaskQuery().taskName(null), usually when the name comes from an unpopulated variable, config value, or optional request parameter.

Common situations: Search screens where the name filter is optional but passed straight through; property files where the expected task name key is missing; beans built before their name field was set.

Related errors

• Error retrieving app engine info
• ids are null
• implementation is null
• key is null
• keyLike is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/4e75b2c52009d511. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-task-service/src/main/java/org/flowable/task/service/impl/TaskQueryImpl.java:239

    }

    @Override
    public TaskQuery taskIds(Collection<String> taskIds) {
        if (taskIds == null) {
            throw new FlowableIllegalArgumentException("Task ids are null");
        }
        if (orActive) {
            currentOrQueryObject.taskIds = taskIds;
        } else {
            this.taskIds = taskIds;
        }
        return this;
    }

    @Override
    public TaskQueryImpl taskName(String name) {
        if (name == null) {
            throw new FlowableIllegalArgumentException("Task name is null");
        }

        if (orActive) {
            currentOrQueryObject.name = name;
        } else {
            this.name = name;
        }
        return this;
    }

    @Override
    public TaskQuery taskNameIn(Collection<String> nameList) {
        if (nameList == null) {
            throw new FlowableIllegalArgumentException("Task name list is null");
        }
        if (nameList.isEmpty()) {
            throw new FlowableIllegalArgumentException("Task name list is empty");
        }

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