quarkusio/quarkus · error · IllegalStateException

Duplicating MultiByteHttpData is not supported

Error message

Duplicating MultiByteHttpData is not supported

What it means

duplicate() on MultiByteHttpData is explicitly unimplemented: the class cannot produce a duplicate FileUpload because its content spans multiple ByteBufs and duplication semantics are not supported. It always throws IllegalStateException.

Source

Thrown at independent-projects/resteasy-reactive/client/runtime/src/main/java/org/jboss/resteasy/reactive/client/impl/multipart/MultiByteHttpData.java:251

    @Override
    public boolean isInMemory() {
        return true;
    }

    @Override
    public File getFile() {
        return null;
    }

    @Override
    public FileUpload copy() {
        throw new IllegalStateException("Copying MultiByteHttpData is not supported");
    }

    @Override
    public FileUpload duplicate() {
        throw new IllegalStateException("Duplicating MultiByteHttpData is not supported");
    }

    @Override
    public FileUpload retainedDuplicate() {
        throw new IllegalStateException("Duplicating MultiByteHttpData is not supported");
    }

    @Override
    public FileUpload replace(ByteBuf content) {
        throw new IllegalStateException("Replacing MultiByteHttpData is not supported");
    }

    @Override
    public FileUpload retain(int increment) {
        super.retain(increment);
        return this;
    }

View on GitHub (pinned to e1c734241f)

Solutions

1. Do not duplicate; construct a fresh MultiByteHttpData and set it with the original content
2. Restructure code to reuse the same instance when sending multiple requests
3. Catch IllegalStateException and rebuild the part from the underlying file/bytes

Example fix

// before
FileUpload dup = fileUpload.duplicate();
// after
FileUpload dup = new MultiByteHttpData(fileUpload.getName(), fileUpload.getFilename(), fileUpload.getContentType(), fileUpload.getCharset());
dup.setContent(fileUpload.getByteBuf());

if (data instanceof MultiByteHttpData) { /* do not call duplicate() */ }

boolean isDuplicable(InterfaceHttpData d) { return !(d instanceof MultiByteHttpData); }

try { return upload.duplicate(); } catch (IllegalStateException e) { return newUploadFrom(upload); }

When it happens

Trigger: Calling FileUpload.duplicate() on a MultiByteHttpData instance, directly or via Netty code that duplicates HttpData objects.

Common situations: Sharing one multipart part across multiple outgoing requests by duplicating it; generic HttpData processing pipelines that clone every part.

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

• setting content of MultiByteHttpData is not supported
• adding content to MultiByteHttpData is not supported
• getting all the contents of a MultiByteHttpData is not suppo
• Reading MultiByteHttpData as String is not supported
• Renaming destination file for MultiByteHttpData is not suppo

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/637bbdc7a0ef7691. Report an issue: GitHub.