Michael Kroll

Originally posted by a sanjuan:
i just realized something...i have Feng and Zhu's Wireless Java Programming with J2ME, and it is also from the same publisher.
deoes your book cover aspects of j2me beyond that covered by the previous (older) book?
[ August 01, 2002: Message edited by: a sanjuan ]

Sure, we cover MIDP and PDAP as well. You will learn how to create the same application using MIDP and PDAP for instance and how to create applications handling PDAPs new PIM API.

Originally posted by Debbie Argulkar:
Hi Michael Kroll and Stefan Haustein,
I have a question for you.
Does the book talk about how to deploy applications and how to access them via the mobile device instead of the emulator?
Regards,
Deb

Hi Deb,
we describe JAM in general. Since some devices have a proprietary OTA mechanism we don't cover different ways to achive it. The JAD file properties are covered, but deployment is described only to the step of creating Jar/Jad file pairs.

Hello,
currently I'm writing a small document for the kobjects.org website how to install JavaComm and CEJavaComm in order to use my CommConnection for ME4SE. This will enable PJava based PDAs to commnicate with a desktop PC over a serial connection or even bluetooth. Hope to get it finished by this weekend.

Originally posted by marion dosh:
Everybody is talking about PDAP but on java.sun.com it is never mentioned. What is PDAP: the MIDP2.0? Or a specialized profile for PDAs?

Right, it is a CLDC Profile for PDAs. Look at
http://jcp.org/aboutJava/communityprocess/review/jsr075/index.html for details.

Originally posted by Keshava Moorthy:
Hi,
I am doing TCK testing on CVM. I am using Compaq PDA with Win CE OS. I am running JAva test Agent on PDA and JAva test main on Windows host PC. While running JAva test main I am getting exception PortInUseException, which means that COM port is already occupied by some other application.
Please suggest me how to solve this problem.
TIA
Keshav

Hi, perhaps your device is located in the cradle and ActiveSync is running using the serial port for syncronization?

Originally posted by Keshava Moorthy:
Can somebody helps me details about serial port communication using JAVA

Hello Keshava,
what do you exaclty want to know about it? Perhaps I send you a code snippet showing you how to open a n Input-/OutputStream on a ComPort.
CommConnection is included in the Public Review Draft of PDAP. (Com port settings etc.)
Here's the code showing you how to handle CommConnections using the Generic Connection Framework:
StreamConnection sc = (StreamConnection)
Connector.open("comm:0;baudrate=9600");

InputStream is = sc.openInputStream();
OutputStream os = sc.openOutputStream();
// add code to read/write here ...
is.close(); // close the streams
os.close();
sc.close(); // close the CommConnection.

Do you need more specific infos?

Originally posted by Robert Paris:
OK, I know that "technically" the java.sun.com website has an explanation of the differences between say Personal Edition Java and Micro-Edition. However, I still don't get it.
Can someone tell me:
1. Why all the different versions? (And what are the differences)
2. Which are still being supported?
2. How do I know when to use one over the other?
Thanks!

Hi Robert,
as I know Personal Java was specified log before J2ME. J2ME consists of two configurations, the CDC (Connected Device Configuration) and the CLDC (Connected Limited Device Configuration). The latter one has two profiles, MIDP (Mobile Information Device Profile) and PDAP (PDA Profile). As you look at the SUN website for CDC there are some mor profiles (RMI, Foundation, Personal Basis Profile, Personal Profile). The CDC and Personal Profile seems to be the successor of PJava whereas PDAP is somewhat below CDC+PP, since PDAP supports most of the PP, but is based on CLDC not on CDC so the java.lang classes are not the same for instance.
The main difference between CDC and CLDC and their proper profiles is the hardware specs. CLDC is specified for devices such as cell phones and low power pdas whereas CDC is specified for high end PDAs and SetTop boxes, Terminals etc.
Still confused?

Hi,

Originally posted by Robert Paris:
No, I disagree. If they ship a hardware impl. of JVM then the push for major advances in making the JVM/JRE protable across all devices and making it as lightweight as possible might stagnate. I'd rather see everyone concentrate on making software JVMs so we can keep researching how to make these superfast/lightweight but powerful.

I think and hope Robert meant that the AWT subset which is included in PDAP is mapped to native widgets which enhances the speed of the VM enourmous compared to a software implementation as we did in kAWT. Or did you mean a real Java-Chip? The new ARM architechture that will be available in PalmOS5.0 would make a powerful JVM implemetation supporting PDAP possible, but I think JVMs such as Jbed would make it as well.
Lets wait for first implemetations and Palms RI before we can speculate about how lightweight they really are.

Hi Mahesh,

Originally posted by mahesh sr:
Hi Michael Kroll and Stefan Haustein,
I am a beginner in J2ME development. Does your book contain stuff to help novice J2ME programmers like me ?
I hope i'll get a copy of your book.
Regards
Mahesh

Yes, the book is intended for developers without J2ME but Java experience. We start describing simple "Hello World" applications for CLDC/MIDP/PDAP describing compilation, preverification and running the app. Then we decribe step by step creating MIDP apps using WTK and describe PDAP step by step as well. So you can use the book to start developing MIDP and PDAP in parallel and see the differences of both APIs. By the way you will learn how to create applications using the same base (RMS and GCF) with sophisticated GUIs. Example Blood Sugar Logger. The app uses the same classes for persistent storage but different UIs.
Hope this helps a little.

Originally posted by Aaron O'Brien:
Hi,
I am interested to find out what this KAWT can do...any examples? Thanks!
SCJP2

kAWT is a subset of J2SE AWT. You can look at http://www.kawt.de to see some samples. I'm doing application development for IPaq and Nokia 9210 using PJava and the same applications can be run on a Palm using kAWT. Look at http://193.25.22.67/mobile/de/programme/index.html the Application uses the same java source for all three applications. That's what kAWT on a Palm can do ;-)

Originally posted by Michael Yuan:
For those who might not know:
Michael Kroll is the author of kAWT, an AWT package ported to KVM.
Stefan Haustein is a lead developer in the EnhydraME project.

We are both working on kAWT. Stefan is leading some enhydra projects and ME4SE. For the latter I'm contributor of the RMS, CommConnection and the FileConnection. Currently we are developing many other ME4SE enhancements which will be available at the website soon.

Juanjo, I forgot to mention, that we added "comparsion charts" in the appendix to provide some kind of reference in order to show J2SE developers which classes and methods are included. For example show the developer which methods of the String class can be used in J2ME.

Hello Juanjo,
the reader of our book should have at least some basic java experience. We don't explain how to use prinitive data types nor explain how to build loops and so on. We introduce the MIDP and PDAP api a low level and create complex examples step by step. For example we start to describe the high-level MIDP api my implementing a small application using a Form and some Textfields only. Then the application is extended by Lists and Choices. After that Commands are added, and so on. We hope to give a developer who is familiar with a good book learing how to deal with MIDP/PDAP apis.

Hello Anders,
yes we have a sample application covering the bouncycastle crypto api in out "thrid party api" chapter. We describe it's features and additionaly present a MIDP sample showing how to crypt and decrypt data. All crypt-api stuff is handled in two methods crypt() and decrypt() in order to simply "cut and paste" the functionality to own applications. But the bouncycastle crypto api is only one of many others that are covered by this chapter, so we have not spend many pages to describe it.

Hello Rishi, Hi Axel,
thanks for the warm welcome. Our book covers MIDP and PDAP application programming as well. Since MIDP4Palm is available you can run MIDP application which are developed using the Wireless Toolkit for instance on the Palm as well. Another good and fast solution to run MIDP applications on a Palm would be to use Jbed from esmertec. In order to run PDAP application we present in the book we recommend to use ME4SE which can be found at http://www.me4se.org, which can be used on a real PDA such as the Compaq IPaq as well.
Yes, we are currently negotiating with a german publisher to create a german book :-)
Perhaps it will be available in some months.
If you got further questions concerning Palm and other J2ME topics don't hesitate to ask me.