flowable/flowable-engine · error · FlowableIllegalStateException

Cannot set both body bytes and form parameters

Error message

Cannot set both body bytes and form parameters

What it means

HttpRequest forbids combining raw bodyBytes with form parameters. setBodyBytes throws FlowableIllegalStateException when formParameters is non-empty, because form-encoded and raw byte payloads are different content types.

Solutions

1. Encode the data as form parameters instead of raw bytes, or clear the form parameters first
2. If bytes are required, start a new HttpRequest without form parameters
3. Set Content-Type appropriately for whichever single payload mode you keep

Example fix

// before
request.addFormParameter("k", "v");
request.setBodyBytes(bytes); // throws
// after
request.setBodyBytes(bytes); // bytes only, no form params

if (request.getFormParameters() != null && !request.getFormParameters().isEmpty()) {
    throw new IllegalStateException("Request is form-encoded; cannot also set bodyBytes");
}
request.setBodyBytes(bytes);

boolean canSetByteBody(HttpRequest r) {
    return r.getFormParameters() == null || r.getFormParameters().isEmpty();
}

try {
    request.setBodyBytes(bytes);
} catch (FlowableIllegalStateException e) {
    request = new HttpRequest();
    request.setBodyBytes(bytes);
}

When it happens

Trigger: Calling request.setBodyBytes(bytes) after addFormParameter(...) calls on the same instance.

Common situations: Reusing a form-submission request for a binary upload; a shared builder that sets default form fields plus a byte body.

Related errors

• Cannot set both body and form parameters
• Cannot set both body and body bytes
• Cannot set both body and multi value parts
• Cannot set both body bytes and multi value parts
• A non-null value is required for one of timeDate…

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/1ebe13354ac18348. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-http-common/src/main/java/org/flowable/http/common/api/HttpRequest.java:130

    public String getBodyEncoding() {
        return bodyEncoding;
    }

    public void setBodyEncoding(String bodyEncoding) {
        this.bodyEncoding = bodyEncoding;
    }

    public byte[] getBodyBytes() {
        return bodyBytes;
    }

    public void setBodyBytes(byte[] bodyBytes) {
        if (body != null) {
            throw new FlowableIllegalStateException("Cannot set both body and body bytes");
        } else if (multiValueParts != null && !multiValueParts.isEmpty()) {
            throw new FlowableIllegalStateException("Cannot set both body bytes and multi value parts");
        } else if (formParameters != null && !formParameters.isEmpty()) {
            throw new FlowableIllegalStateException("Cannot set both body bytes and form parameters");
        }
        this.bodyBytes = bodyBytes;
    }

    public Collection<MultiValuePart> getMultiValueParts() {
        return multiValueParts;
    }

    public void addMultiValuePart(MultiValuePart part) {
        if (body != null) {
            throw new FlowableIllegalStateException("Cannot set both body and multi value parts");
        } else if (bodyBytes != null) {
            throw new FlowableIllegalStateException("Cannot set both body bytes and multi value parts");
        } else if (formParameters != null && !formParameters.isEmpty()) {
            throw new FlowableIllegalStateException("Cannot set both form parameters and multi value parts");
        }
        if (multiValueParts == null) {
            multiValueParts = new ArrayList<>();

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