apache/dubbo · error · IllegalStateException

url missing protocol: "${fullURLStr}"

Error message

url missing protocol: "${fullURLStr}"

What it means

Thrown by URLStrParser.parseURLBody as an IllegalStateException when the URL string contains the '://' separator at position 0, i.e. the protocol segment before '://' is empty. The parser cannot determine a protocol, so it rejects the malformed URL rather than guessing.

Source

Thrown at dubbo-common/src/main/java/org/apache/dubbo/common/URLStrParser.java:114

    /**
     * @param fullURLStr  : fullURLString
     * @param decodedBody : format: [protocol://][username:password@][host:port]/[path]
     * @param parameters  :
     * @return URL
     */
    private static URL parseURLBody(String fullURLStr, String decodedBody, Map<String, String> parameters) {
        int starIdx = 0, endIdx = decodedBody.length();
        // ignore the url content following '#'
        int poundIndex = decodedBody.indexOf('#');
        if (poundIndex != -1) {
            endIdx = poundIndex;
        }

        String protocol = null;
        int protoEndIdx = decodedBody.indexOf("://");
        if (protoEndIdx >= 0) {
            if (protoEndIdx == 0) {
                throw new IllegalStateException("url missing protocol: \"" + fullURLStr + "\"");
            }
            protocol = decodedBody.substring(0, protoEndIdx);
            starIdx = protoEndIdx + 3;
        } else {
            // case: file:/path/to/file.txt
            protoEndIdx = decodedBody.indexOf(":/");
            if (protoEndIdx >= 0) {
                if (protoEndIdx == 0) {
                    throw new IllegalStateException("url missing protocol: \"" + fullURLStr + "\"");
                }
                protocol = decodedBody.substring(0, protoEndIdx);
                starIdx = protoEndIdx + 1;
            }
        }

        String path = null;
        int pathStartIdx = indexOf(decodedBody, '/', starIdx, endIdx);
        if (pathStartIdx >= 0) {

View on GitHub (pinned to 3a3043227f)

Solutions

1. Supply a non-empty protocol before '://' in the URL string (e.g. 'dubbo://', 'nacos://', 'zookeeper://').
2. Fix the config interpolation so the protocol variable resolves to a real value in the active profile.
3. Validate URL strings before parsing: assert they match <nonempty>:// before passing to URLStrParser.

Example fix

// before
String u = "://" + host + ":" + port + "/" + path; // protocol empty -> throws

// after
String u = protocol + "://" + host + ":" + port + "/" + path; // protocol non-empty

// Validate the URL shape before parsing
if (url == null || url.startsWith("://") || (url.contains("://") && url.indexOf("://") == 0)) {
    throw new IllegalArgumentException("url missing protocol: " + url);
}
URL parsed = URLStrParser.parseURL(url);

When it happens

Trigger: Parsing a URL string that starts with '://' (e.g. "://host:port/path") via URLStrParser / valueOf paths; a URL built by concatenation where the protocol variable was empty before '://'; a config placeholder for the protocol that resolved to empty string.

Common situations: Config templating where ${protocol} is unset and yields '://host...'; string concatenation building a URL with an empty protocol field; copy-paste removing the protocol; environment/profile that fails to inject the protocol variable; malformed registry/address strings parsed at startup.

Related errors

• Invalid url, password without username!
• Invalid url, password without username!
• The address of metadata report is invalid.
• Invalid configurator rule, please specify at least one param
• service field in configuration is null.

AI-assisted analysis of apache/dubbo@3a3043227f (2026-08-14). Data as JSON: /api/errors/04833a4ecb51fe2b. Report an issue: GitHub.