フリー問題

問題文

A servlet reads an incoming stream without blocking its thread. What attaches the object that will do the reading, and which callback tells that object about fresh bytes?

選択肢

1. The stream is attached through the call that sets a read listener, and the reading object hears about fresh bytes through the callback for data at a halt
2. The stream is attached through the call that sets a read listener, and the reading object hears about fresh bytes through the callback for data at hand
3. The stream is attached through the call that sets a read limit, and the reading object hears about fresh bytes through the callback for data at hand
4. The stream is attached through the call that sets a read limit, and the reading object hears about fresh bytes through the callback for data at a halt