There are a lot of reasons that you might need to use a mobile phone’s bluetooth when you are developing a software for cell phones. Instead of creating your own library of mobile phone bluetooth functions, you can just use an existing bluetooth library for mobile phones.

Bluetooth has been increasingly incorporated into mobile phone devices. Several reasons may exist why your application needs to use the available bluetooth device — connect to another mobile phone to initiate a file transfer, play a multiplayer game using bluetooth, send a message using the mobile phone’s bluetooth, chat over bluetooth, stream sound to a headset.

If you’re creating a multiplayer game that needs to use the mobile phone’s bluetooth you can use an existing library built for multiplayer games over bluetooth or try to develop one on your own.

An existing library for creating multiplayer bluetooth-enabled mobile phone games is available at Bluetooth at Work. The sourceforge project provides a library, called BTLib, for developing multi-client mobile applications communicating via bluetooth.

They have also developed several multiplayer via bluetooth games that you can also download to learn how to use the library that they have developed. The multiplayer via bluetooth include battleship and Cervii that runs on mobile phone devices.

You can also download the software if you want to learn more about programming / accessing bluetooth on a mobile phone. Checkout the Bluetooth at Work project at sourceforge.

Books you can buy about J2ME and bluetooth:

• Bluetooth For Java by Bruce Hopkins and Ranjith Antony
• J2ME Games With MIDP2 by Carol Hamer
• J2ME: The Complete Reference by James Edward Keogh
• Enterprise J2ME: Developing Mobile Java Applications by Michael Juntao Yuan
• Wireless Game Development in Java with MIDP 2.0 (Wordware Game Developer’s Library) by Ralph Barbagallo