flowable/flowable-engine · error · ActivitiIllegalArgumentException

Error Code must not be empty.

Error message

Error Code must not be empty.

What it means

Besides being non-null, a BpmnError errorCode must have length >= 1. setErrorCode() throws ActivitiIllegalArgumentException("Error Code must not be empty.") when an empty string is supplied, because an empty code can never be matched by any error boundary event definition.

Solutions

1. Provide a real non-empty error code matching the errorCode attribute of the boundary/error start event in the BPMN XML.
2. Trim and check before throwing: if (code == null || code.trim().isEmpty()) code = fallback.
3. Fix the upstream data source producing the empty string.

Example fix

// before
throw new BpmnError(errorCode); // errorCode == ""
// after
if (errorCode == null || errorCode.trim().isEmpty()) {
    errorCode = "UNSPECIFIED_ERROR";
}
throw new BpmnError(errorCode);

if (errorCode == null || errorCode.trim().isEmpty()) errorCode = "UNSPECIFIED_ERROR";

boolean isNonEmpty(String s) { return s != null && !s.trim().isEmpty(); }

try { serviceCall(); } catch (ActivitiIllegalArgumentException e) { if (e.getMessage().contains("must not be empty")) { throw new BpmnError("FALLBACK_CODE"); } throw e; }

When it happens

Trigger: new BpmnError("") or new BpmnError(message, "") — constructors receiving an empty-string error code.

Common situations: Error code read from a config file / process variable / DB column that is empty string rather than null; string building that produced "" (e.g. split or substring yielding empty).

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Error code must not be empty.
• Error Code must not be null.
• ' ' is not valid boolean in mapException with errorCode=…
• Error code must not be null.
• ${errorCode}

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/f39f85b73cf8c57a. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable5-engine/src/main/java/org/activiti/engine/delegate/BpmnError.java:52

    private String errorCode;

    public BpmnError(String errorCode) {
        super("");
        setErrorCode(errorCode);
    }

    public BpmnError(String errorCode, String message) {
        super(message + " (errorCode='" + errorCode + "')");
        setErrorCode(errorCode);
    }

    protected void setErrorCode(String errorCode) {
        if (errorCode == null) {
            throw new ActivitiIllegalArgumentException("Error Code must not be null.");
        }
        if (errorCode.length() < 1) {
            throw new ActivitiIllegalArgumentException("Error Code must not be empty.");
        }
        this.errorCode = errorCode;
    }

    public String getErrorCode() {
        return errorCode;
    }

    @Override
    public String toString() {
        return super.toString() + " (errorCode='" + errorCode + "')";
    }

}

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