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If you are trying, from your Android application through the Android emulator, to access an external service on the same computer (such as your own Google App Engine site) by using the host name localhost or the IP-address 127.0.0.1, you might get a java.net.ConnectException
java.net.ConnectException: localhost/127.0.0.1:8888 - Connection refused error - even though you can perfectly well access the service outside the Android application.
The reason why a ConnectException occurs is because "localhost" or "127.0.0.1" inside the Android emulator is the emulator's own loopback interface, meaning all request sent to the destination will be looped backed to the emulator and won't actually be sent to your local machine.
To by pass this, simply replace "localhost" with the IP-address "10.0.2.2", as this is a special address towards the real local host.
Done!
