CloseableHttpClient
is the base class of the httpclient library, the one all implementations use. Other subclasses are for the most part deprecated.
The HttpClient
is an interface for this class and other classes.
You should then use the CloseableHttpClient
in your code, and create it using the HttpClientBuilder
. If you need to wrap the client to add specific behaviour you should use request and response interceptors instead of wrapping with the HttpClient
.
This answer was given in the context of httpclient-4.3.