org.apache.http.conn.HttpHostConnectException: Connection to http://10.0.2.2:80 refused

 org.apache.http.conn.HttpHostConnectException: Connection to http://10.0.2.2:80 refused

This exception occurs when you want to invoke from your emulator an url from apache ,using for example wamp or easyphp.
To resolve it you must add 10.0.2.2 to be allowed on the file of configuration of apache server.
So go to Apache httpd.conf (located in Apache folder): and search for

Order Deny,Allow
Deny from all
Allow from 127.0.0.1

and check if the second line is Deny, if it is then change it to:

Allow from all