Create a Android Java object for a static nested class.

I tried to created a object for following java static nested class

https://cs.chromium.org/chromium/sr...5cd1cfb7c439e3229249677ff18e5922addc5ed5&l=57

AndroidJavaClass playerClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
AndroidJavaObject activity = playerClass.GetStatic<AndroidJavaObject>("currentActivity");
AndroidJavaClass peerConnectionFactoryClass = new AndroidJavaClass("org.webrtc.PeerConnectionFactory");
AndroidJavaObject builderObject = new AndroidJavaObject("org.webrtc.PeerConnectionFactory.InitializationOptions.Builder", new object[1] {activity});

And always got error message
AndroidJavaException: java.lang.ClassNotFoundException: org.webrtc.PeerConnectionFactory.InitializationOptions.Builder

org.webrtc.PeerConnectionFactory.InitializationOptions also cannot be found, although, org.webrtc.PeerConnectionFactory can be found.

Does anyone know how to create java object for static nested classes. I appreciate all helps.