flowable/flowable-engine · error · FlowableIllegalArgumentException

categoryLike is null

Error message

categoryLike is null

What it means

Flowable's AppDefinitionQueryImpl validates every query criterion before storing it. Calling appDefinitionCategoryLike(null) throws FlowableIllegalArgumentException because a null 'like' pattern cannot be translated into a SQL LIKE clause. The check happens eagerly at query-building time, not at query execution.

Source

Thrown at modules/flowable-app-engine/src/main/java/org/flowable/app/engine/impl/repository/AppDefinitionQueryImpl.java:95

            throw new FlowableIllegalArgumentException("Empty appsDefinitionIds");
        }
        this.ids = appsDefinitionIds;
        return this;
    }

    @Override
    public AppDefinitionQueryImpl appDefinitionCategory(String category) {
        if (category == null) {
            throw new FlowableIllegalArgumentException("category is null");
        }
        this.category = category;
        return this;
    }

    @Override
    public AppDefinitionQueryImpl appDefinitionCategoryLike(String categoryLike) {
        if (categoryLike == null) {
            throw new FlowableIllegalArgumentException("categoryLike is null");
        }
        this.categoryLike = categoryLike;
        return this;
    }

    @Override
    public AppDefinitionQueryImpl appDefinitionCategoryNotEquals(String categoryNotEquals) {
        if (categoryNotEquals == null) {
            throw new FlowableIllegalArgumentException("categoryNotEquals is null");
        }
        this.categoryNotEquals = categoryNotEquals;
        return this;
    }

    @Override
    public AppDefinitionQueryImpl appDefinitionName(String name) {
        if (name == null) {
            throw new FlowableIllegalArgumentException("name is null");

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Check the value for null before calling appDefinitionCategoryLike, and only call it when non-null
2. Default the value to a non-null pattern (e.g. "%") if a match-all is intended
3. If a null means 'no filter', restructure to conditionally apply the criterion
4. Catch FlowableIllegalArgumentException at the API boundary and return a 400 with the message

Example fix

// before
query.appDefinitionCategoryLike(categoryLike);
// after
if (categoryLike != null) {
    query.appDefinitionCategoryLike(categoryLike);
}

if (categoryLike != null) {
    query.appDefinitionCategoryLike(categoryLike);
}

boolean isApplicable(String v) { return v != null && !v.isEmpty(); }

try {
    query.appDefinitionCategoryLike(categoryLike);
} catch (FlowableIllegalArgumentException e) {
    throw new ResponseStatusException(HttpStatus.BAD_REQUEST, e.getMessage(), e);
}

When it happens

Trigger: Calling appDefinitionQuery.appDefinitionCategoryLike(categoryLike) with a null String, typically when the value comes from an unset/unbound variable, a missing request parameter, or a caller that builds criteria conditionally but passes the variable unconditionally.

Common situations: REST/API layers binding optional query params (categoryLike not supplied -> null); code refactored so a previously-defaulted value became nullable; dynamic query builders that always call every filter method.

Related errors

• categoryNotEquals is null
• name is null
• nameLike is null
• key is null
• keyLike is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/2ab418d78a65007e. Report an issue: GitHub.