ServiceFactory单例模式的实现方式，锁的粒度也太大了吧，高并发下会严重影响性能

`public static final synchronized ServiceFactory getInstance() throws SdkInitException
   {
     if (serviceFactory != null) {
      return serviceFactory;
    }
     return getInstance(new DefaultConfig());
 }`

锁直接加载了方法方法上，高并发下性能会比较差
