I\'ve two android applications on same LAN provided by WIFI :
You may confuse two different level of networking communication.
Level 4 : TCP connection between two sockets.
A logical pipe between to side (may be single(two process?) or two different computers)
only connection handling data are handle at this level
Level 7 : Browser / Application Server used particular communication "language" to exchange high level data (file , images, audio ..) and is handled at this level.
Your question is about to open a Listening Socket (level 4) and a client that talk with it with a HTTP protocol (level 7).
So you're miss to fill the gap socket listening side to handle HTTP protocol
May be a java web server implementation may help you.
a Java EE way to have HTTP server : "Tiny Java Web Server" @ http://tjws.sourceforge.net/ that may help you for what you're looking for
an "Apache" way to have HTTP server http://www.androiddevblog.net/android/a-bare-minimum-web-server-for-android-platform
see
http://en.wikipedia.org/wiki/OSI_model#Layer_3:_Network_Layer
to have more complete view of these Communication Layer
Listening on a port and accepting socket connections isn't enough to serve data back to HttpClient. Sockets in effect provide a physical pipe but know nothing about the format of the data that's flowing along that pipe. If you are set on using HttpClient, then you'll need to have your server application understand HTTP protocol (or at least a very basic subset of it).
If all you need is to have two processes communicate in some way, you may be better off having your server app be a service and then your client app interrogate this service for the required data.
I was looking for the same solution and found NanoHTTPD - an extremely simple HTTP request handling server class. You can find the source and very easy to understand samples at https://github.com/NanoHttpd