flowable/flowable-engine · error · FlowableIllegalArgumentException

type is required when adding a new task identity link

Error message

type is required when adding a new task identity link

What it means

AddIdentityLinkCmd requires a non-null identityType (e.g. assignee, owner, participant) to categorize the identity link being added to a task. A null type would produce an ambiguous link, so validateParams throws FlowableIllegalArgumentException.

Source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/cmd/AddIdentityLinkCmd.java:56

    protected String identityType;

    public AddIdentityLinkCmd(String taskId, String identityId, int identityIdType, String identityType) {
        super(taskId);
        validateParams(taskId, identityId, identityIdType, identityType);
        this.taskId = taskId;
        this.identityId = identityId;
        this.identityIdType = identityIdType;
        this.identityType = identityType;
    }

    protected void validateParams(String taskId, String identityId, int identityIdType, String identityType) {
        if (taskId == null) {
            throw new FlowableIllegalArgumentException("taskId is null");
        }

        if (identityType == null) {
            throw new FlowableIllegalArgumentException("type is required when adding a new task identity link");
        }

        if (identityId == null && (identityIdType == IDENTITY_GROUP ||
                (!IdentityLinkType.ASSIGNEE.equals(identityType) && !IdentityLinkType.OWNER.equals(identityType)))) {

            throw new FlowableIllegalArgumentException("identityId is null");
        }

        if (identityIdType != IDENTITY_USER && identityIdType != IDENTITY_GROUP) {
            throw new FlowableIllegalArgumentException("identityIdType allowed values are 1 and 2");
        }
    }

    @Override
    protected Void execute(CommandContext commandContext, TaskEntity task) {
        CmmnEngineConfiguration cmmnEngineConfiguration = CommandContextUtil.getCmmnEngineConfiguration(commandContext);
        
        String oldAssigneeId = task.getAssignee();

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Pass a valid IdentityLinkType constant (ASSIGNEE, OWNER, PARTICIPANT, etc.) to the call
2. If the type comes from external input, validate/map it to a known IdentityLinkType before invoking
3. Default to IdentityLinkType.PARTICIPANT when no specific semantics are needed

Example fix

// before
taskService.addUserIdentityLink(taskId, userId, linkType); // linkType == null
// after
taskService.addUserIdentityLink(taskId, userId,
    linkType != null ? linkType : IdentityLinkType.PARTICIPANT);

if (linkType == null) throw new IllegalArgumentException("identity type is required");
taskService.addUserIdentityLink(taskId, userId, linkType);

boolean hasType(String type) { return type != null && !type.isBlank(); }

try {
    taskService.addUserIdentityLink(taskId, userId, type);
} catch (FlowableIllegalArgumentException e) {
    log.warn("Invalid identity link call: {}", e.getMessage());
}

When it happens

Trigger: Calling cmmnTaskService.addUserIdentityLink(taskId, userId, null) or addGroupIdentityLink(taskId, groupId, null), or constructing AddIdentityLinkCmd with a null type argument.

Common situations: Type read from config/property file that is missing, a constant refactored away, passing an enum's null value after a failed lookup, or a REST client omitting the type field.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• userId and groupId cannot both be null
• Either set the user id or the group id for an identity link,
• taskId is null
• identityId is null
• identityIdType allowed values are 1 and 2

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/195ae0e0fdc1c4e3. Report an issue: GitHub.