@Override
    public synchronized void patchConnectorConfig(String connName, Map<String, String> configPatch, Callback<Created<ConnectorInfo>> callback) {
        try {
            ConnectorInfo connectorInfo = connectorInfo(connName);
            if (connectorInfo == null) {
                callback.onCompletion(new NotFoundException("Connector " + connName + " not found", null), null);
                return;
            }

            Map<String, String> patchedConfig = ConnectUtils.patchConfig(connectorInfo.config(), configPatch);
            validateConnectorConfig(patchedConfig, (error, configInfos) -> {
                if (error != null) {
                    callback.onCompletion(error, null);
                    return;
                }

                requestExecutorService.submit(
                        () -> putConnectorConfig(connName, patchedConfig, null, true, callback, configInfos)
                );
            });
        } catch (Throwable e) {
            callback.onCompletion(e, null);
        }
    }
Single process, in-memory "herder". Useful for a standalone Kafka Connect process.
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/standalone/StandaloneHerder.java