What causes "Provided groupId is null" in flowable/flowable-engine?

Pass a valid, existing group id string.

flowable/flowable-engine · error · FlowableIllegalArgumentException

Provided groupId is null

Error message

Provided groupId is null

What it means

UserQueryImpl.memberOfGroup(String) throws FlowableIllegalArgumentException when the groupId argument is null. The engine requires an explicit group id to filter users by membership. Pass a real group id or don't call memberOfGroup().

Source

Thrown at modules/flowable-idm-engine/src/main/java/org/flowable/idm/engine/impl/UserQueryImpl.java:213

            throw new FlowableIllegalArgumentException("Provided email is null");
        }
        this.email = email;
        return this;
    }

    @Override
    public UserQuery userEmailLike(String emailLike) {
        if (emailLike == null) {
            throw new FlowableIllegalArgumentException("Provided emailLike is null");
        }
        this.emailLike = emailLike;
        return this;
    }

    @Override
    public UserQuery memberOfGroup(String groupId) {
        if (groupId == null) {
            throw new FlowableIllegalArgumentException("Provided groupId is null");
        }
        this.groupId = groupId;
        return this;
    }

    @Override
    public UserQuery memberOfGroups(List<String> groupIds) {
        if (groupIds == null) {
            throw new FlowableIllegalArgumentException("Provided groupIds is null");
        }
        this.groupIds = groupIds;
        return this;
    }

    @Override
    public UserQuery tenantId(String tenantId) {
        if (tenantId == null) {
            throw new FlowableIllegalArgumentException("TenantId is null");

View on GitHub (pinned to d6d39ce1c6)

Solutions

Pass a valid, existing group id string.
Guard: only call memberOfGroup() when groupId != null.
If multiple groups are possible, use memberOfGroups(List<String>) with a non-null list instead.

Example fix

// before
UserQuery q = identityService.createUserQuery().memberOfGroup(task.getGroupId());
// after
UserQuery q = identityService.createUserQuery();
if (task.getGroupId() != null) {
    q = q.memberOfGroup(task.getGroupId());
}

Defensive patterns

Strategy: validation

Validate before calling

if (groupId != null) { query = query.memberOfGroup(groupId); }

Type guard

boolean hasGroupId(String id) { return id != null && !id.isBlank(); }

Try / catch

try { query.memberOfGroup(groupId); } catch (FlowableIllegalArgumentException e) { log.warn("Null groupId filter ignored", e); }

Prevention

Resolve group ids from a reliable source and check for null before use
Skip membership filtering when no group is assigned
Log which caller passed a null group id to catch bad resolution logic early

When it happens

Trigger: Calling identityService.createUserQuery().memberOfGroup(null).

Common situations: A group variable resolved from configuration, a tenant lookup, or an assignment rule comes back null and is forwarded directly into the query.

Related errors

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/7822b8f4369efeeb. Report an issue: GitHub.