First check the Javadocs for that API (included in all SDK installations). There are also sample MIDlets and documentation available on Forum Nokia Web site. You can also find information by reading Forum Nokia Discussion Boards and Sun’s Java ME Web site.
And finally check also JavaTM ME Developer's Library on Forum Nokia.
With Bluetooth capable devices, you can send the JAR and JAD files over Bluetooth using the File Browser. You can also use PC Suite.
An advanced option is to store the JAR and JAD files on a Web server
and connect to the JAD file using the phone browser. Make sure the mime types
are set correctly on the server (“application/java-archive”
for JAR and “text/vnd.sun.j2me.app-descriptor” for JAD).
For more information on deploying, see also section Deploying MIDlets to a device.
All SDKs contain an emulator, which basically emulates the phone Java
environment and the set of APIs included in that SDK on your PC. When you
run your MIDlet in the emulator, you can see diagnostic information (like printStackTrace() output)
in the console screen.
You should always test your application on a real device as some of the phone capabilities cannot be emulated on PC. Also there are subtle differences in the phone implementations.
For more information signing MIDlets, see the section Signed MIDlets.