flowable/flowable-engine · error · FlowableIllegalStateException

Cannot set both body and multi value parts

Error message

Cannot set both body and multi value parts

What it means

HttpRequest forbids combining a String body with multi value (multipart) parts. setBody throws FlowableIllegalStateException when multipart parts have already been added, because a request cannot carry both a plain body and multipart form data.

Solutions

1. Remove the setBody call and pass any extra fields as additional multi value parts
2. If a plain body is needed, build a separate HttpRequest without addMultiValuePart calls
3. Clear/reset the request (new instance) before switching payload styles

Example fix

// before
request.addMultiValuePart(MultiValuePart.fromBytes(file, "f.bin"));
request.setBody("meta"); // throws
// after
request.addMultiValuePart(MultiValuePart.fromString("meta", "meta.txt"));

if (request.getMultiValueParts() != null && !request.getMultiValueParts().isEmpty()) {
    throw new IllegalStateException("Request is multipart; cannot also set a String body");
}
request.setBody(body);

boolean canSetStringBody(HttpRequest r) {
    return r.getMultiValueParts() == null || r.getMultiValueParts().isEmpty();
}

try {
    request.setBody(body);
} catch (FlowableIllegalStateException e) {
    request = new HttpRequest();
    request.setBody(body); // drop multipart parts
}

When it happens

Trigger: Calling request.setBody(text) after request.addMultiValuePart(part) was used on the same instance.

Common situations: Adding a file part for an upload and then trying to also set a JSON/plain body on the same request; reusing a request object configured for multipart in a plain-body context.

Related errors

• Cannot set both body bytes and multi value parts
• Cannot set both body and body bytes
• Cannot set both body and form parameters
• Cannot set both body bytes and form parameters
• Cannot set both form parameters and multi value parts

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/01a70a0f2ee22b7f. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-http-common/src/main/java/org/flowable/http/common/api/HttpRequest.java:105

    }

    public String getSecureHttpHeadersAsString() {
        return secureHttpHeaders != null ? secureHttpHeaders.formatAsString(true) : null;
    }

    public void setSecureHttpHeaders(HttpHeaders secureHttpHeaders) {
        this.secureHttpHeaders = secureHttpHeaders;
    }

    public String getBody() {
        return body;
    }

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

    public String getBodyEncoding() {
        return bodyEncoding;
    }

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

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

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