ClientProtocolException contradicts tutorial statement in chapter 1.4

Chapter 1.4 says: "HttpClient can throw two types of exceptions: java.io.IOException in case of an I/O failure such as socket timeout or an socket reset and HttpException that signals an HTTP failure such as a violation of the HTTP protocol. Usually I/O errors are considered non-fatal and recoverable, whereas HTTP protocol errors are considered fatal and cannot be automatically recovered from."

The Javadoc of ClientProtocolException says: "Signals an error in the HTTP protocol." Given the definition established in the tutorial, either one is incorrect. Either ClientProtocolException must derive from HttpException or its documentation must be contrary to the latter.