public synchronized static boolean configureFactory(
            InternalLogFactory factory) {
        if (factory == null)
            throw new IllegalArgumentException();
        if (factoryConfigured)
            return false;
        InternalLogFactory.factory = factory;
        factoryConfigured = true;
        return true;
    }
Used to explicitly configure the log factory. The log factory can only be
configured at most once. All subsequent configurations will have no
effect.

Note explicitly configuring the log factory will have positive
performance impact on all subsequent logging, since the specific logger
can be directly referenced instead of being searched every time.

@param factory
           the log factory to be used internally by the SDK

@return true if the log factory is successfully configured; false
        otherwise (ie the log factory is not allowed to be configured
        more than once for performance reasons.)
aws-java-sdk-core/src/main/java/com/amazonaws/log/InternalLogFactory.java