quarkusio/quarkus · error · IllegalArgumentException

Invalid server address

Error message

Invalid server address 

What it means

Quarkus parses each host in `hosts` into a MongoDB ServerAddress, splitting on ':' to allow host or host:port. If an entry splits into more than 2 segments (or is otherwise malformed), the parser rejects it with this IllegalArgumentException.

Source

Thrown at extensions/mongodb-client/runtime/src/main/java/io/quarkus/mongodb/runtime/MongoClients.java:514

        }

        return addresses.stream()
                .map(String::trim)
                .map(new addressParser()).collect(Collectors.toList());
    }

    private static class addressParser implements Function<String, ServerAddress> {
        @Override
        public ServerAddress apply(String address) {
            String[] segments = COLON_PATTERN.split(address);
            if (segments.length == 1) {
                // Host only, default port
                return new ServerAddress(address);
            } else if (segments.length == 2) {
                // Host and port
                return new ServerAddress(segments[0], Integer.parseInt(segments[1]));
            } else {
                throw new IllegalArgumentException("Invalid server address " + address);
            }
        }
    }

    private MongoCredential createMongoCredential(MongoClientConfig config) {

        // get the authsource, or the database from the config, or 'admin' as it is the default auth source in mongo
        // and null is not allowed
        String authSource = config.credentials().authSource().orElse(config.database().orElse("admin"));
        // AuthMechanism
        AuthenticationMechanism mechanism = null;
        Optional<String> maybeMechanism = config.credentials().authMechanism();
        if (maybeMechanism.isPresent()) {
            mechanism = getAuthenticationMechanism(maybeMechanism.get());
        }

        UsernamePassword usernamePassword = determineUserNamePassword(config.credentials());
        if (usernamePassword == null) {

View on GitHub (pinned to e1c734241f)

Solutions

1. Use `host` or `host:port` per entry — put credentials/database in `connection-string` instead of `hosts`
2. Wrap IPv6 addresses in brackets: `[::1]:27017`
3. Remove stray commas/whitespace from the hosts list
4. Prefer `quarkus.mongodb.connection-string` entirely for complex setups

Example fix

// before
quarkus.mongodb.hosts=user:pass@mongo.example.com:27017
// after
quarkus.mongodb.connection-string=mongodb://user:pass@mongo.example.com:27017

// Validate hosts entries before use
for (String h : hosts.split(",")) {
    String v = h.trim();
    if (v.isEmpty()) throw new IllegalArgumentException("Empty host entry");
    int colon = v.indexOf(':');
    if (colon != v.lastIndexOf(':') && v.indexOf('[') < 0) {
        throw new IllegalArgumentException("Malformed host (extra ':'): " + v);
    }
    if (colon >= 0 && Integer.parseInt(v.substring(colon + 1, v.indexOf(']') > 0 ? v.length() : v.length())) > 65535) {
        throw new IllegalArgumentException("Invalid port: " + v);
    }
}

When it happens

Trigger: Configuring `quarkus.mongodb.hosts` with a value like `host1:27017:extra`, an IPv6 literal without brackets, an empty host entry, or a full connection string pasted into the hosts property.

Common situations: Copying a `mongodb://user:pass@host:port/db` URI into the hosts field (the ':' in user:pass creates extra segments); writing bare IPv6 addresses like ::1 instead of [::1]:27017; trailing commas producing empty segments.

Related errors

• Invalid duration: ${value}
• Config property 'quarkus.mongodb.database' must be defined w
• <errorMessage>.formatted(clientName) (required Liquibase Mon
• Mongo client named '%s' not found
• Mongo Client '%s' is not active

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/99ce7f1922b4e84c. Report an issue: GitHub.