General MIDLet questions: networking, MIDLet size, Bluetooth, LBS

[theAntSki]

Hi all,
I have some very general questions:

1. There was another posting similar to this but just in case someoness misses that - how does the MIDP connectivity work - does it require a cellphone call or GPRS or... - how is the HTTP/TCP/IP message actually sent to my webserver container?

2. How serious is the the cellphones' JAR size limit (e.g. 30k on 6310i)? Can anything be done about it e.g. upgrade hardware? How small is 30K - can you do anything useful with it? I come from the J2EE world where 30K is nothing...

3. Bluetooth: I saw on another posting that there is no Bluetooth API for the J2ME world. Is that true? This seems to be a serious shortcoming - there must someone working on this as I write this, right...?

4. LBS: Does anyone know what is the state of the art in Location Based Services (LBS)? I am specifically interested in doing LBS on ordinary cellphones - well atleast MIDP+WAP+GPRS, but no addditional GPS device or attachment...

Cheers and tx in advance.
Ant.

[sabineheine]

Hi Ant,

1. Any connection from the phone to a server will require either a circuit-switched (GSM) phone call or an open (packet-switched) GPRS session if the phone has that capability. The data is sent from the phone via the cellular network to the server and vice-versa.

2. The maximum midlet size is set by the manufacturer and will depend on the memory available in the phone, which tends to sit around the 300kb mark. The physical size of the phone means you can't just keep adding processors to increase memory. The 7650 has 4MB, so this will go up, but phones aren't servers.
You can do a fair amount with 30kb, have a look around this site and the net for various examples. You're on the opposite extreme to J2EE here. There is a wireless Java bit on the Sun developer site which explains some more and has some examples inlcuding how to use J2EE to do the computation for a J2ME application and send the results back via the network.

3. The bluetooth API together with a whole load of other APIs are in the process of being standardised: http://www.jcp.org/jsr/detail/82.jsp
Hopefully this will be on the handsets shortly afterwards.

4. A location API is also currently going through the JSR process (no 179). The phone has a pretty good idea of its location by triangulating between base stations, so no GPS attachement needed unless you want it down to the nearest 100m.

cheers,
Sabine

[pbergius]

Hi Ant,

Further to the location based service: Creating location based service on the phone is currently practically impossibe. Phone does know of network characteristics (RX level, timing advance, etc.) relative to several base stations. Unfortunately it doesn't know their exact geographical locations, which renders network info practically useless.

The only good way to develop LBS applications is to get location from LIF (Location Information Forum) compliant location server of an operator. Approximate location is returned as geocoordinates. Many operators are currently rolling out these services, most of them are even accessible to outside developers.

There is a GPS module called LAM-1 available for Nokia 9210 (see http://www.nokia.com/phones/gps_module/index.html). Unfortunaly it doesn't currently have API for PersonalJava or MIDP.

Regards,

Petteri / Forum Nokia

[kookywon]

Is there any additional information about LIF compliant location server operators? Are there any companies that provide this service yet? URLs?

[applebypd]

Try this URL for up to date(ish) information http://www.openmobilealliance.org/tech/workprogram.htm

Regards

Pete

[r2j7]

Hello theAntSki,

3. Bluetooth: I saw on another posting that there is no Bluetooth API for the J2ME world. Is that true? ..

No, actually Bluetooh API is already there for J2ME application development. For further information, please check the following link:

http://www.forum.nokia.com/info/sw.n..._0_en.pdf.html

As for devices supporting Bluetooth API, all devices can be found on the page: http://www.forum.nokia.com/devices/matrix_all_1.html

(From the specs of each device, JSR 82 Bluetooth API is listed under Java Technology if supported by the device)

Regards,
r2j7

[NoOneCanHelpMe]

Hi everyone, I don't know who do have to I turn to, but can anyone help with one problem, I bought nokia 5300 and I cant access internet through an application, but I enter every site with the built in browser, I tryed every settings, tried with automatic settings from Nokia site, from o2 mobile operator's site but with no result at all, I am with the newest firmware.
Could anyone suggest me sth because I think that is a problem with the java platform.
Shall I return the phone and buy a new one?
PLEASE HELP ME, I WOULD BE VERY GRATEFUL
THANK YOU IN ADVANCE

[r2j7]

Hello NoOneCanHelpMe,

please see if these instructions by Hartti could help:

http://blogs.forum.nokia.com/blog/ha...6XcKZUa6EMQ-20

Regards,
r2j7