t8y2/dbx · error · IllegalArgumentException

Unsupported JDBC plugin method: " + method

Error message

Unsupported JDBC plugin method: " + method

What it means

DbxJdbcPlugin.handle dispatches JSON-RPC plugin methods to typed calls via a switch; the default arm throws IllegalArgumentException for any method name the JDBC plugin does not implement. This guards against unknown or unsupported RPC methods rather than failing later with a confusing NullPointerException or wrong-argument error.

Source

Thrown at plugins/jdbc/src/main/java/app/dbx/jdbc/DbxJdbcPlugin.java:475

                optionalText(params, "schema"),
                requireText(params, "name"),
                requireText(params, "object_type")
            );
            case "getColumns" -> getColumns(
                connection,
                optionalText(params, "database"),
                optionalText(params, "schema"),
                requireText(params, "table")
            );
            case "getExplainInfo" -> getExplainInfo(
                connection,
                requireText(params, "sql"),
                optionalText(params, "database"),
                optionalText(params, "schema"),
                nonNegativeInt(params, "timeoutSecs", -1),
                optionalText(params, "mode")
            );
            default -> throw new IllegalArgumentException("Unsupported JDBC plugin method: " + method);
        };
    }

    private static ObjectNode connectionTestResult(Connection connection) {
        ObjectNode result = MAPPER.createObjectNode();
        result.put("ok", true);
        ObjectNode databaseInfo = databaseInfo(connection);
        if (!databaseInfo.isEmpty()) {
            result.set("databaseInfo", databaseInfo);
        }
        return result;
    }

    private static ObjectNode databaseInfoResult(Connection connection) {
        ObjectNode result = MAPPER.createObjectNode();
        ObjectNode databaseInfo = databaseInfo(connection);
        if (!databaseInfo.isEmpty()) {
            result.set("databaseInfo", databaseInfo);

View on GitHub (pinned to c0390bff16)

Solutions

1. Check the plugin's supported method list and send an exact, correctly-cased method name.
2. Align client and plugin versions so the method exists on both sides.
3. Catch IllegalArgumentException in handleLine's caller and return a JSON-RPC 'method not found' error to the client instead of crashing the dispatch.

Example fix

// before
send("jdbc.executeQuery", params); // wrong method name
// after
send("jdbc.query", params); // exact supported method name

Set<String> JDBC_METHODS = Set.of(/* e.g. "connect","query","execute",... as documented for the plugin */);
if (!JDBC_METHODS.contains(method)) {
    // reject client-side before sending the RPC
}

try {
    result = plugin.handle(method, params);
} catch (IllegalArgumentException e) {
    if (e.getMessage().startsWith("Unsupported JDBC plugin method")) {
        respond(method, jsonRpcError(-32601, "Method not found: " + method));
    } else throw e;
}

When it happens

Trigger: Sending a JSON-RPC request to the JDBC plugin whose "method" is not one of the handled names — e.g. a typo like "query.execute", a method added in a newer plugin version but sent to an older plugin, or a method belonging to a different plugin (e.g. a MongoDB-only method) routed to the JDBC plugin.

Common situations: Client/server version mismatch where the caller assumes a method exists; hand-written test payloads with misspelled method names; generic tooling that broadcasts the same method to all plugins; case-sensitivity issues ("Query" vs "query").

Related errors

• JDBC pool registry must be attached before connecting
• Not connected
• JDBC Session was quarantined while waiting for a connection
• Object source is not supported
• Completion assistant search is not supported by this agent

AI-assisted analysis of t8y2/dbx@c0390bff16 (2026-09-05). Data as JSON: /api/errors/d1adbe53327647a0. Report an issue: GitHub.