The best replacement for httpclient is httpurlconnection.

The best alternatives to httpclient are rated as following:
★★★★★  httpurlconnection
★★★★  webclient
★★★★  urlconnection
★★★  httpwebrequest
★★★  webrequest
★★★  restsharp
★★★  webrequest c#
★★★  httpcore
★★  httpurlconnection android
★★  resttemplate
★★  jersey client
★  commons-httpclient
★  defaulthttpclient
★  httpcomponents
★  htmlunit
★  androidhttpclient
  jsoup
  commons httpclient
  httpurlconnection java

Your alternative for httpclient is not listed? Suggest!
Speaking about httpclient, one probably shouldn't forget about https.

Other search terms related to httpclient and their ratings are:
★★★★★ https
★★ ntlm authentication
resttemplate
You have in mind a companion for httpclient and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of httpclient in all years. Click on graph for more.
httpclient
httpurlconnection
webclient