When someone want to buy a new or used car, he can make better decision if he can find out cars data and which dealers sell the cars. It takes a lot of time if someone going around visiting car dealers and seeking cars data. Using Java enterprise (J2EE), desktop (J2SE) & mobile (J2ME) technology a software for searching and ordering car was built. The Java enterprise application part implemented using Enterprise Java Bean (EJB) and Web Service resides on a server which serve as central database for desktop and mobile application. Java desktop application part installed at car dealers. Car dealers use this application to maintain their cars data and calculating car selling forecast using lagrange method. Java mobile application part installed on user cell phone or PDA as MIDlet application used to search cars & dealers data and order cars. The software leveraging internet and GPRS/3G technology.