necessity of JAD in OTA ???

[Punit Raizada]

Hi All,

This is my understanding of the OTA :
- JAD is required.
- JAD contains the URL that points to the JAR file in the MIDlet-Jar-URL attribute..(This is where the phone finds the JAR)

Now,
I was reading the MIDP 2.0 spec (JSR 118) and something is bothering me .. i just might be understanding it incorrectly.

on Page 13 (PDF) , Chapter 2 OTA , Section MIDlet Suite Discovery
2nd Paragraph
"Using the DA, the user SHOULD be able to access a network location and see a description of the MIDlet suite along with a link that, when selected , initiates the installation of the MIDlet suite. If the link refers to a JAR file as described in the MIDP specification, the JAR and its URL are passed back to the AMS on the device to start the installation process. ....."


My question :

Is it possible to implement the download of a MIDlet suite by only giving the jar and not the JAD .. isnt the MIDlet size also checked in the JAD to determine if there is enough memory on the device ??? and some other stuff...

I will try it out at work tommorrow ... I am sure I am understanding the wording of this paragraph incorrectly...

Any one has any comments ???

[Roseanne Zhang]

Yes, you can, just you download any zip/rar/jar file by using a browser.

Try it, then you would know.

[Punit Raizada]

hmmm...

I send only the JAR file through bluetooth during our development stage and it gets installed ... but i was under the impression that a JAD was necessary for OTA ...

Learn something new every night

[Sathya Srinivasan]

JAD is not necessary, but recommended for the following reasons.

1. If you install jut the JAR file, then the app will be treated as 'untrusted' (read security in J2ME for more details).
2. The minimum requirement to make an app 'trusted' is to have a JAD file. A trusted app, much like a trusted applet, has more access.
3. As you mentioned, you can also mention more parameters in the JAD file that would help the device be better prepared for the app.

I have a Sony T610 and I always send only the JAR file (can't even seem to get the JAD file installed!)

[Punit Raizada]

Yup,

Sony Ericsson phones dont keep the JAD file in the phone .. i bet during OTA they download the JAD .. read and verify the signatures and other stuff but dont store it.

PS: Sathya .. your notes are real nice ..

[Roseanne Zhang]

Originally posted by Sathya Srinivasan:
I have a Sony T610 and I always send only the JAR file (can't even seem to get the JAD file installed!)

That is correct, since Sony T610 does not accept jad file.

[Sathya Srinivasan]

Originally posted by Punit Raizada:
Yup,

PS: Sathya .. your notes are real nice ..

Thanks for the remarks. Glad to be of help.