AT or attention are set of commands those are used to communicate with GSM modems.I am not going much about it as you can google it.I tried using the AT commands through Bluetooth which was successful and finally integrated it to JAVA so that I can send message through my mobile using an interface instead of hyper-terminal.Before getting it started check your mobile if it supports the commands or not by using Hyper-terminal or any serial port Software.
In the below codes i have used RxTx serial communication library that is free to use and my communication port was 'COM9' please check it for you and then changing it compile the code.
Main.java //Main GUI
package com.oksbwn.Y2014.Message_Mobile; import java.awt.Color; import java.awt.Dimension; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import javax.swing.*;