apache/pulsar · error · IOException

(no message; URI missing for data: URL connection)

Error message

(no message; URI missing for data: URL connection)

What it means

DataURLStreamHandler's connection lazily parses the data: URL on connect(). If the connection was created without a URI (no URL was actually supplied), it throws a bare IOException with no message. Callers like getInputStream, getContentType, and getContentLengthLong all funnel through connect().

Source

Thrown at pulsar-common/src/main/java/org/apache/pulsar/client/api/url/DataURLStreamHandler.java:68

              "(?<mimeType>[^;,]+)?(;(?<charset>charset=[^;,]+))?(;(?<base64>base64))?,(?<data>.+)", Pattern.DOTALL);

        protected DataURLConnection(URL url) {
            super(url);
            try {
                this.uri = this.url.toURI();
            } catch (URISyntaxException e) {
                this.uri = null;
            }
        }

        @Override
        public void connect() throws IOException {
            if (this.parsed) {
                return;
            }

            if (this.uri == null) {
                throw new IOException();
            }

            Matcher matcher = pattern.matcher(this.uri.getSchemeSpecificPart());
            if (matcher.matches()) {
                this.contentType = matcher.group("mimeType");
                if (contentType == null) {
                    this.contentType = "application/data";
                }

                if (matcher.group("base64") == null) {
                    // Support Urlencode but not decode here because already decoded by URI class.
                    this.data = matcher.group("data").getBytes(StandardCharsets.UTF_8);
                } else {
                    this.data = Base64.getDecoder().decode(matcher.group("data"));
                }
            } else {
                throw new MalformedURLException();
            }

View on GitHub (pinned to 820761864e)

Solutions

1. Verify the URL string is a well-formed data: URL (data:[<mime>[;base64]],<data>) before opening the connection.
2. Construct the URL from a proper spec string so URI resolution succeeds, e.g. new URL("data:text/plain;base64,SGVsbG8=").
3. If building the handler manually, ensure the URL passed to openConnection actually carries a URI; catch the IOException and log the source URL for diagnosis.

Example fix

// before
URL url = new URL(null, someUnvalidatedString, new DataURLStreamHandler());
url.openStream();
// after
if (someUnvalidatedString == null || !someUnvalidatedString.startsWith("data:")) {
    throw new IllegalArgumentException("not a data URL: " + someUnvalidatedString);
}
URL url = new URI(someUnvalidatedString).toURL(); // ensures URI is resolvable

if (urlString == null || !urlString.startsWith("data:")) {
    throw new IllegalArgumentException("expected a data: URL, got: " + urlString);
}

try (InputStream in = dataUrl.openStream()) {
    // read
} catch (IOException e) {
    // empty message means URI was missing; log the URL string used
}

When it happens

Trigger: Invoking openConnection/openStream/getContent on a data: URLStreamHandler where URL.getURL's URI is null — typically constructing the URL without a valid context or with an empty/unsupported spec so URI resolution fails.

Common situations: Programmatically constructing a URL with new URL(null, spec, new DataURLStreamHandler()) where the spec cannot be converted to a URI; framework code passing an unset/empty data payload; URL encoding issues that break URI parsing.

Related errors

• (no message; malformed data: URL)
• Cursor %s mark-delete position %s is ahead of the last posit
• Timeout during reset cursor
• Timeout during mark-delete operation
• Could not open configuration file

AI-assisted analysis of apache/pulsar@820761864e (2026-09-06). Data as JSON: /api/errors/a6155ace219af7af. Report an issue: GitHub.