What causes "Task descriptionLikeIgnoreCase is null" in flowable/flowable-engine?

Skip the criterion when the value is null (conditional query building).

flowable/flowable-engine · error · FlowableIllegalArgumentException

Task descriptionLikeIgnoreCase is null

Error message

Task descriptionLikeIgnoreCase is null

What it means

TaskQuery.taskDescriptionLikeIgnoreCase() throws FlowableIllegalArgumentException when the argument is null. Besides being non-null, the value is lowercased by the method itself to enable case-insensitive matching, so it must be a real string before the call.

Solutions

Skip the criterion when the value is null (conditional query building).
Provide a default non-null pattern value at the DTO/controller layer.
Use Optional.ofNullable(desc).ifPresent(query::taskDescriptionLikeIgnoreCase) style guards.
Catch FlowableIllegalArgumentException at the boundary and return 400.

Example fix

// before
query.taskDescriptionLikeIgnoreCase(filter);
// after
if (filter != null) {
    query.taskDescriptionLikeIgnoreCase(filter);
}

Defensive patterns

Strategy: validation

Validate before calling

if (descriptionLikeIgnoreCase != null) {
    query.taskDescriptionLikeIgnoreCase(descriptionLikeIgnoreCase);
}

Type guard

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

Try / catch

try {
    query.taskDescriptionLikeIgnoreCase(value);
} catch (FlowableIllegalArgumentException e) {
    throw new BadRequestException("descriptionLikeIgnoreCase must not be null", e);
}

Prevention

Guard all IgnoreIgnoreCase criteria: they require non-null values for toLowerCase().
Normalize optional filters to absent (skip) rather than null (throw).
Keep filter-building code in one place so null checks are never forgotten.
Cover optional-filter paths with tests that pass null explicitly.

When it happens

Trigger: Calling taskDescriptionLikeIgnoreCase(null); passing an optional filter from a search request where the parameter was absent.

Common situations: Case-insensitive search endpoints with optional description filters; upstream services sending JSON objects without the field, deserialized to null.

Related errors

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/e70da16ec05baf70. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-task-service/src/main/java/org/flowable/task/service/impl/TaskQueryImpl.java:378

    }

    @Override
    public TaskQuery taskDescriptionLike(String descriptionLike) {
        if (descriptionLike == null) {
            throw new FlowableIllegalArgumentException("Task descriptionlike is null");
        }
        if (orActive) {
            currentOrQueryObject.descriptionLike = descriptionLike;
        } else {
            this.descriptionLike = descriptionLike;
        }
        return this;
    }

    @Override
    public TaskQuery taskDescriptionLikeIgnoreCase(String descriptionLikeIgnoreCase) {
        if (descriptionLikeIgnoreCase == null) {
            throw new FlowableIllegalArgumentException("Task descriptionLikeIgnoreCase is null");
        }
        if (orActive) {
            currentOrQueryObject.descriptionLikeIgnoreCase = descriptionLikeIgnoreCase.toLowerCase();
        } else {
            this.descriptionLikeIgnoreCase = descriptionLikeIgnoreCase.toLowerCase();
        }
        return this;
    }

    @Override
    public TaskQuery taskPriority(Integer priority) {
        if (priority == null) {
            throw new FlowableIllegalArgumentException("Priority is null");
        }
        if (orActive) {
            currentOrQueryObject.priority = priority;
        } else {
            this.priority = priority;

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