flowable/flowable-engine · error · FlowableException

variableListenerEventDefinition is only supported for events

Error message

variableListenerEventDefinition is only supported for events, not for activity id ${parentElement.getId()}

What it means

The converter maps a variableListenerEventDefinition child element to an event definition, but this definition is only meaningful on event elements (catch/intermediate/boundary events). If the parent activity is a task, service task, etc., Flowable throws a FlowableException naming the offending activity id.

Source

Thrown at modules/flowable-bpmn-converter/src/main/java/org/flowable/bpmn/converter/child/VariableListenerEventDefinitionParser.java:38

import org.flowable.bpmn.model.BpmnModel;
import org.flowable.bpmn.model.Event;
import org.flowable.bpmn.model.VariableListenerEventDefinition;
import org.flowable.common.engine.api.FlowableException;

/**
 * @author Tijs Rademakers
 */
public class VariableListenerEventDefinitionParser extends BaseChildElementParser {

    @Override
    public String getElementName() {
        return ELEMENT_EVENT_VARIABLELISTENERDEFINITION;
    }

    @Override
    public void parseChildElement(XMLStreamReader xtr, BaseElement parentElement, BpmnModel model) throws Exception {
        if (!(parentElement instanceof Event event)) {
            throw new FlowableException("variableListenerEventDefinition is only supported for events, not for activity id " + parentElement.getId());
        }
        
        VariableListenerEventDefinition eventDefinition = new VariableListenerEventDefinition();
        BpmnXMLUtil.addXMLLocation(eventDefinition, xtr);
        
        String variableName = xtr.getAttributeValue(null, ATTRIBUTE_VARIABLE_NAME);
        if (StringUtils.isEmpty(variableName)) {
            LOGGER.warn("variable name is required for variable listener with activity id {}", parentElement.getId());
        }
        eventDefinition.setVariableName(variableName);
        
        String variableChangeType = xtr.getAttributeValue(null, ATTRIBUTE_VARIABLE_CHANGE_TYPE);
        eventDefinition.setVariableChangeType(variableChangeType);

        event.addEventDefinition(eventDefinition);
        
        model.addActivityIdForVariableListenerName(variableName, parentElement.getId());
    }

View on GitHub (pinned to d6d39ce1c6)

Solutions

  1. Move the variableListenerEventDefinition into an event element (e.g. intermediateCatchEvent) that references the same activity id
  2. Remove the variableListenerEventDefinition from the non-event element
  3. Redeploy the corrected BPMN XML

Example fix

<!-- before -->
<serviceTask id="task1">
  <flowable:variableListenerEventDefinition variableName="v"/>
</serviceTask>
<!-- after -->
<intermediateCatchEvent id="evt1">
  <flowable:variableListenerEventDefinition variableName="v"/>
</intermediateCatchEvent>
Defensive patterns

Strategy: try-catch

Try / catch

try { bpmnXMLConverter.convertToBpmnModel(xmlInput); } catch (FlowableException e) { /* move event definition into an Event element */ }

Prevention

When it happens

Trigger: BPMN XML places <flowable:variableListenerEventDefinition> inside a non-event activity (e.g. a serviceTask or userTask) instead of an intermediateCatchEvent or boundaryEvent.

Common situations: Hand-edited XML moving event definitions between elements; refactoring a task into an event but forgetting to move the child definition; modeler exports with misplaced children.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/81fd563db72b118d. Report an issue: GitHub.