GPS in j2me-enabled mobile phones
Just because a phone can run J2ME doesn't mean that the manufacturer has placed a GPS unit in it. As far as I know, there are mobile phones that can run Java applications but do not have built-in GPS. If you want to find the location of your phone, you can resort to triangulation where you use cell towers to find your phone. However, this method offers at best a relatively large margin of error.
If the triangulation mechanism doesn't work for you, you will have to restrict your application to only GPS enabled phones.
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