@Override
    public ElementRegistry get() {
        ElementRegistry result = registry;
        if (result == null) {
            synchronized (this) {
                result = registry;
                if (result == null) {
                    registry = result = create();
                }
            }
        }

        return result;
    }
Implements an idiom to prevent double checked locking.
stroom-pipeline/src/main/java/stroom/pipeline/factory/ElementRegistryFactoryImpl.java