branch : master , version : 2.7.0-SNAPSHOT
ServiceConfig#doExportUrlsFor1Protocol , line 482

<img width="890" alt="image" src="https://user-images.githubusercontent.com/6971152/41273922-035827c2-6e4e-11e8-8a72-71562d138cf9.png">

The type of Constant.SCOPE_Xxx is String already , no need to call toString() again
}
            if (delay == null) {
                delay = provider.getDelay();
            }
        }
        if (export != null && !export) {
            return;
        }
        if (delay != null && delay > 0) {
            delayExportExecutor.schedule(new Runnable() {
                @Override
                public void run() {
                    doExport();
                }
            }, delay, TimeUnit.MILLISECONDS);
        } else {
            doExport();
        }
    }
    protected synchronized void doExport() {
        if (unexported) {
            throw new IllegalStateException("Already unexported!");
        }
        if (exported) {
            return;
        }
        exported = true;
        if (interfaceName == null || interfaceName.length() == 0) {
            throw new IllegalStateException("<dubbo:service interface=\"\" /> interface not allow null!");
        }