flowable/flowable-engine · warning · FlowableObjectNotFoundException

The variable does not have a binary data stream.

Error message

The variable does not have a binary data stream.

What it means

FlowableObjectNotFoundException from the historic case instance variable data endpoint: the variable's value is not a byte-array/serializable type, so there is no binary stream to download. Only ByteArray and Serializable variables expose raw data.

Source

Thrown at modules/flowable-cmmn-rest/src/main/java/org/flowable/cmmn/rest/service/api/history/caze/HistoricCaseInstanceVariableDataResource.java:81

    public byte[] getVariableData(@ApiParam(name = "caseInstanceId") @PathVariable("caseInstanceId") String caseInstanceId, 
                    @ApiParam(name = "variableName") @PathVariable("variableName") String variableName, HttpServletResponse response) {
        try {
            byte[] result = null;
            RestVariable variable = getVariableFromRequest(true, caseInstanceId, variableName);
            if (CmmnRestResponseFactory.BYTE_ARRAY_VARIABLE_TYPE.equals(variable.getType())) {
                result = (byte[]) variable.getValue();
                response.setContentType("application/octet-stream");

            } else if (CmmnRestResponseFactory.SERIALIZABLE_VARIABLE_TYPE.equals(variable.getType())) {
                ByteArrayOutputStream buffer = new ByteArrayOutputStream();
                ObjectOutputStream outputStream = new ObjectOutputStream(buffer);
                outputStream.writeObject(variable.getValue());
                outputStream.close();
                result = buffer.toByteArray();
                response.setContentType("application/x-java-serialized-object");

            } else {
                throw new FlowableObjectNotFoundException("The variable does not have a binary data stream.", null);
            }
            return result;

        } catch (IOException ioe) {
            // Re-throw IOException
            throw new FlowableException("Unexpected exception getting variable data", ioe);
        }
    }

    public RestVariable getVariableFromRequest(boolean includeBinary, String caseInstanceId, String variableName) {
        HistoricCaseInstance caseObject = getHistoricCaseInstanceFromRequest(caseInstanceId);

        HistoricVariableInstance variable = historyService.createHistoricVariableInstanceQuery()
                        .caseInstanceId(caseObject.getId())
                        .variableName(variableName)
                        .singleResult();

        if (variable == null || variable.getValue() == null) {

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Only request data endpoints for byte-array or serializable variables; read plain values via the variable JSON endpoint
2. Check the variable's type field in the variable response before fetching data
3. Fix the case definition so the variable is stored as byte array/Serializable if binary data is expected
4. Handle the 404/FlowableObjectNotFoundException client-side with a graceful fallback

Example fix

// before
byte[] data = restClient.getVariableData(caseId, varName); // fails for String vars
// after
VariableResponse v = restClient.getVariable(caseId, varName);
byte[] data = "byteArray".equals(v.getType()) ? restClient.getVariableData(caseId, varName) : null;

if (!"byteArray".equals(variable.getType()) && !"serializable".equals(variable.getType()))
  return null; // no binary data to fetch

boolean hasBinaryData(VariableResponse v) {
  return "byteArray".equals(v.getType()) || "serializable".equals(v.getType());
}

try { return resource.getVariableData(caseId, varName); }
catch (FlowableObjectNotFoundException e) {
  log.info("Variable {} has no binary data", varName);
  return null;
}

When it happens

Trigger: GET of variable data for a historic case variable whose stored value is a plain String/Integer/etc. rather than a byte[] or Serializable payload.

Common situations: Client assumes every variable has downloadable data; variable type changed between case versions (was a document byte array, now a string); querying the wrong variable name.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Could not find a case instance
• Could not find a plan item instance
• Plan item instance '${instanceId}' doesn't have a variable w
• Case instance '${instanceId}' doesn't have a variable with n
• Plan item instance '${id}' does not have a variable '${varia

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/4e20adaa590469e0. Report an issue: GitHub.