apache/maven · error · TransferFailedException

Unsupported Protocol: '" + protocol + "': " + e.getMessage()

Error message

Unsupported Protocol: '" + protocol + "': " + e.getMessage()

What it means

Error "Unsupported Protocol: '" + protocol + "': " + e.getMessage()" thrown in apache/maven.

Source

Thrown at compat/maven-compat/src/main/java/org/apache/maven/repository/legacy/DefaultWagonManager.java:319

    @SuppressWarnings("checkstyle:methodlength")
    @Override
    public void getRemoteFile(
            ArtifactRepository repository,
            File destination,
            String remotePath,
            TransferListener downloadMonitor,
            String checksumPolicy,
            boolean force)
            throws TransferFailedException, ResourceDoesNotExistException {
        String protocol = repository.getProtocol();

        Wagon wagon;

        try {
            wagon = getWagon(protocol);
        } catch (UnsupportedProtocolException e) {
            throw new TransferFailedException("Unsupported Protocol: '" + protocol + "': " + e.getMessage(), e);
        }

        if (downloadMonitor != null) {
            wagon.addTransferListener(downloadMonitor);
        }

        File temp = new File(destination + ".tmp");

        temp.deleteOnExit();

        boolean downloaded = false;

        try {
            connectWagon(wagon, repository);

            boolean firstRun = true;
            boolean retry = true;

View on GitHub (pinned to e4093d4e12)

When it happens

Trigger: Thrown at compat/maven-compat/src/main/java/org/apache/maven/repository/legacy/DefaultWagonManager.java:319 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/maven@e4093d4e12 (2026-08-21). Data as JSON: /api/errors/47e5dc1b21f12cea. Report an issue: GitHub.