j2se ->j2me

[Daniel]

Hello all.
I have an application written in java 1.4.2 standrad edition using
javax.comm. Now my employer wonders how much work it would be to
convert it to handheld devices, i.e mobile edition.
I understand no-one here can really answer that question, but as I
have not worked with j2me at all I'm a bit at loss. So Any advice is
welcome. It is a graphical application using swing.

I guess it could be divided into subclasses

1. Complete rewrite of the code, from scratch, basically no code is
reusable

2. Most code must be rewritten to fit the new platform

3. Basically only the graphical parts must be re-written.

I have no previous experience with j2me, so I don't know what is
available and what is not available compared to "normal" java.

regards
Daniel

 

[Andrew Thompson]

..as I
have not worked with j2me at all I'm a bit at loss. So Any advice is
welcome.

You might find some of your questions answered in
'The JavaME Frequently Asked Questions List'.

..It is a graphical application using swing.

The UI classes available to J2ME are different to
either AWT or Swing.

Further, though I have not worked with J2ME myself, those
who have assure me that most Swing programmers are a little
surprised at just how little memory is available on these
devices.

It might be best to download the basic J2ME dev. kit and
write a couple of little 'hello world' type projects to
get a feel for it.

HTH

 

[Darryl Pierce]

Hello all.
I have an application written in java 1.4.2 standrad edition using
javax.comm. Now my employer wonders how much work it would be to
convert it to handheld devices, i.e mobile edition.
I understand no-one here can really answer that question, but as I
have not worked with j2me at all I'm a bit at loss. So Any advice is
welcome. It is a graphical application using swing.

I guess it could be divided into subclasses

1. Complete rewrite of the code, from scratch, basically no code is
reusable

2. Most code must be rewritten to fit the new platform

3. Basically only the graphical parts must be re-written.

No, you should be able to use some of your classes. The main difference
between JavaSE and MIDP[1] is that the MIDP doesn't have Swing, AWT,
NIO, alot of the resource intensive APIs, etc. from JavaSE. So, any user
interface code is going to have to be replaced. However, business logic
classes that aren't tied to classes that are unavailable in the MIDP[1]
(for example, the Collections classes or the NIO classes, which are
aren't available in the MIDP) will run just fine on a handset.

I have no previous experience with j2me, so I don't know what is
available and what is not available compared to "normal" java.

First recommendation: check out the JavaME FAQ
<http://mcpierce.mypage.org/javamefaq.html>

Second recommendation: pick up a good book, such as Eric Giguere's or
Jonathan Knudsen's MIDP book and read it. It will go a long way towards
helping you since there is a steep, though short, learning curve
involved in MIDP development.

Third recommendation: join the KVM-INTEREST mailing list
<http://archives.java.sun.com/kvm-interest.html> and ask questions of
people who work with the MIDP every day.

HTH.

[1] - JavaME/J2ME refers to all smaller-than-desktop technologies for
Java. But, when most people talk about this, they're really talking
about the MIDP (Mobile Information Device Profile), which is the Java
that's available on mobile devices.

 

[Darryl Pierce]

You might find some of your questions answered in
'The JavaME Frequently Asked Questions List'.
<http://bellsouthpwp.net/m/c/mcpierce/j2mefaq.html>

Thanks for the plug. I've changed the URL, though. It's now
<http://mcpierce.mypage.org/javamefaq.html> to reflect the new naming
from Sun for the Java technologies.

 

[Andrew Thompson]

Thanks for the plug. I've changed the URL, though.

"Cool URL's don't change" Will you be setting up
a permanent redirect from the old URL?

..It's now <http://mcpierce.mypage.org/javamefaq.html>

The link in the JavaFAQ has been updated.

...are those damn pop-ups coming from your page, or has
my machine been mal-wared again? I'll have to run a
checker.

...wait a second...

<FRAMESET rows="100%,*" border=0 frameborder=0 framespacing=0
framecolor="#000000">
<FRAME src="http://../javamefaq.html" name="thepage">
<FRAME src="http://.../domain-names-V3/domain-names.html" name="adpage">

Hidden frames?!? Bad for useability, and makes
things like copying link anchors (which no longer
appear in address bar) harder.

With pop-up ads..

It was really *much* better before.

to reflect the new naming from Sun..

....hmmm. Does that mean the URL will now
'alter with the changing breeze'? :-(

 

[Darryl Pierce]

"Cool URL's don't change" Will you be setting up
a permanent redirect from the old URL?

Yep, there's one there now.

The link in the JavaFAQ has been updated.

...are those damn pop-ups coming from your page, or has
my machine been mal-wared again? I'll have to run a
checker.

They're from V3.org, the redirector service I use. I'm cheap, I've never
had an idea for a permanent domain name or anything, so I've been using
them.

Hidden frames?!? Bad for useability, and makes
things like copying link anchors (which no longer
appear in address bar) harder.

With pop-up ads..

It was really *much* better before.

You can still use the bellsouthpwp.net URL, but if I switch ISPs that
URL will become invalid. I've got to get around to registering a domain
and setting up my own web server...

....hmmm. Does that mean the URL will now
'alter with the changing breeze'? :-(

No. But, since Sun has rechristened all Java editions, it makes sense to
keep the name consistent. As long as Sun doesn't make an annual
"renaming of the javas" holiday, we'll be good.

 

[Andrew Thompson]

Andrew Thompson wrote:

They're from V3.org, the redirector service I use. I'm cheap,

So am I! But domains cost as little as US$16-17 / year
(or less) through places like voxdomains and godaddy.

Heck. *I'll* pay for the domain name for the first year,
just to get rid of those (irritating, noisome) pop-ups.

..I've never
had an idea for a permanent domain name or anything,

darrylpierce.info / darrylpierce.org /
microedition.org / .info .....

(all/any of the above)

..so I've been using them.

<blunt>
That is the single most pathetic excuse I have
heard all week. And that is saying something!
</blunt>

....

No. But, since Sun has rechristened all Java editions, it makes sense to
keep the name consistent. As long as Sun doesn't make an annual
"renaming of the javas" holiday, we'll be good.

(shakes head sadly) I'll get the albatross.
We're doomed, DOOMED, I tell's ya'!

 

[Roedy Green]

Thanks for the plug. I've changed the URL, though. It's now
<http://mcpierce.mypage.org/javamefaq.html> to reflect the new naming
from Sun for the Java technologies.

I have added links to your new FAQ in the Java glossary.

I try to write overview entries to give people a rough idea of what
the pieces are for.

Would it be reasonably correct to say that:

CLDC
MIDP
Personal Basis
Personal Profile

represent ever richer APIs?

J2ME itself does not fit in that list.

 

[Roedy Green]

Jonathan Knudsen's MIDP book

I take it you mean
http://www.amazon.com/exec/obidos/ASIN/1590594797/canadianmindprod
Beginning J2ME: From Novice to Professional, Third Edition

 

[Roedy Green]

Second recommendation: pick up a good book, such as Eric Giguere's

you mean:

Mobile Information Device Profile for Java 2 Micro Edition (J2ME):
Professional Developer's Guide

or
Java 2 Micro Edition: Professional Developer's Guide

or both?

 

[Roedy Green]

No. But, since Sun has rechristened all Java editions, it makes sense to
keep the name consistent. As long as Sun doesn't make an annual
"renaming of the javas" holiday, we'll be good.

I guess Giguere and Ortiz at http://j2medeveloper.com/ won't be happy
about the name change.

 

[Roedy Green]

CLDC
MIDP
Personal Basis
Personal Profile

Here is my tentative list based on rooting about the Internet.

There are a set of APIs, starting from smallest to biggest, roughly
they go: KVM (128K RAM), CLDC (160K RAM), MIDP 1.0 Profile (288K RAM),
CDC (2MB RAM), MIDP 2.0 Profile, Personal Basis Profile, Personal
Profile.

 

[Andrew Thompson]

I guess Giguere and Ortiz at http://j2medeveloper.com/ won't be happy
about the name change.

Note that they can also grab jmedeveloper for just $7.85/year
at vox domains (the price seems dependent on the provider!)

Do you have a contact for them? I do not see one on the site.

 

[Roedy Green]

Note that they can also grab jmedeveloper for just $7.85/year
at vox domains (the price seems dependent on the provider!)

Do you have a contact for them? I do not see one on the site.

The concern is not the registration fee, it is that some remora will
be sitting on the name they need. The remora would see the name change
need coming and scoop up their rightful name.

I will add VOX to the list of domain providers at
http://mindprod.com/jgloss/domainnames.com It is pleasing to see
getting a domain name evolve from a secret Masonic rite to something
grandma does to surprise the twins.

 

[Andrew Thompson]

The concern is not the registration fee, it is that some remora will
be sitting on the name they need.

I checked it was available, before I made comment.

The remora would see the name change
need coming and scoop up their rightful name.

The organisation that handles disputes about domain
name allocations has clamped down on the 'squatters'.

Unless they can show an actual site that backs up their
domain name in a meaningful way, they would most likely lose
the name to the folks that deserve it.

The public comment (by a largely disinterested party)
suggesting that the domain name might be suitable for
the j2medeveloper folks, should seal it.

Any 'remora' would be wasting only a little of the time
of the rightful owner (..and $7.85).

 

[Darryl Pierce]

I guess Giguere and Ortiz at http://j2medeveloper.com/ won't be happy
about the name change.

Hehe, never thought about that. I'll have to ask them...

 

[Darryl Pierce]

Andrew Thompson wrote:

<blunt>
That is the single most pathetic excuse I have
heard all week. And that is saying something!
</blunt>

Ow! Right in the nose too! Someone get me a tissue!

Okay, I've succumbed to peer pressure and have registered mcpierce.org
as my domain with voxdomain.com. You can now go to
http://www.mcpierce.org/javamefaq.html to see the JavaME FAQ.

Jeez, thought I was above ever giving in to peer pressure...

 

[Andrew Thompson]

You can now go to http://www.mcpierce.org/javamefaq.html

Damn fine domain name (and no risk of Sun messing with it).

...to see the JavaME FAQ.

Yay! The PhySci Java FAQ has been updated accordingly.

....

Jeez, thought I was above ever giving in to peer pressure...

We all gotta' roll in the mud, sometimes. ;-)

 

[Roedy Green]

http://www.mcpierce.org/javamefaq.html to see the JavaME FAQ.

if you forget, it listed under FAQs in the Java glossary at

http://mindprod.com/jgloss/faqs.html

 

[Darryl Pierce]

Would it be reasonably correct to say that:

CLDC
MIDP
Personal Basis
Personal Profile

represent ever richer APIs?

J2ME itself does not fit in that list.

Not sure what you mean. J2ME/JavaME is just an umbrella term for the
various Java technologies for handheld, embedded and headless devices.
CLDC and CDC define configurations (VMs and the core APIs available to
those VMs) while MIDP, Personal Basis Profile and Personal Profile are
profiles that reside on top of one of the other configuration, with
Personal Basis being a subset of the Personal Profile.