Past days I experienced a weird problem building and running a midlet with Antenna inside Eclipse. Each time I built and run the application, the WTK "DefaultColorPhone" emulator I used had the RMS completely deleted. Everything was fine if I exited from the appliction and started again without any building.

The solution has been going to the Windows current user "Documents and Settings" folder and browse in "j2mewtk\2.5.2\appdb\DefaultColorPhone". There I found a file in.use that was the lock for the existent RMS and that was the reason why the WTK generated a new clean RMS each time I built the application. Deleting it everything is ok again.

I'm so glad to have the chance to present a J2ME application helping the supporters to keep track of the results of the Italian soccer league Serie A. This midlet has been created by an Italian developer, Stefano Russello.
The application shows the league fixtures and can store the matches results producing automatically the league table with the statistic information for each team. The matches results storing can be manual or automatic. In the first case the user will write the matches result, in the second one the application will get the results after a connection to a server.

Furthermore the midlet presents information about the teams such as geographic position, the stadium and the home and away shirts. The graphic interface is nice and intuitive. The application can be used fully after paying a registration fee of 5 euros (through PayPal) but the user can try a demo version for free before buying the license.

On device debug has been always a headache source for every j2me developers. When you run the application on an emulator you can always use the System.out.prinln instruction (remember to use a method that make possible leave out this log code when you deploy your application) and see the result in the console windows but the same result is not easy reachble when the midlet is running in a real device.

Personally I've created my simple logging structure that write information in a specific screen of the application that you can view clicking on some digits of the phone keyboard.

Two days ago I received a message from a Linkedin group that contained a link to this log library called Microlog, an open source project of a j2me logging library.

This library is build thinking at Log4j and supports logging to:

console, file, RecordStore, Canvas, Form, Bluetooth, a serial port (Bluetooth, IR, USB), Socket(incl SSL), UDP, Syslog, MMS, SMS, e-mail or to Amazon S3

The following are the key features:

• Easy to setup. Configuration via the application descriptor, dependency injection or a property file.
• Similar to Log4j, but built from scratch.
• Small
• Fast
• Many different Appenders
  • ConsoleAppender - Appends to the console, e.g. System.out.
  • RecordStoreAppender - Appends to the RecordStore.
  • FileAppender - Appends to a file using a FileConnection.
  • CanvasAppender - Appends to a Canvas.
  • FormAppender - Appends to a Form.
  • BluetoothSerialAppender - Appends to a Bluetooth serial connection (btspp).
  • SerialAppender - Appends to a serial port (CommConnection).
  • SmsAppender - Appends to a cyclic buffer and send the buffer as an SMS.
  • MmsAppender (for MMS and/or e-mail) - Appends to a cyclic buffer and send the buffer as an SMS.
  • DatagramAppender - Appends to a datagram and send it using UDP.
  • SyslogAppender - Appends to syslog server.
  • SocketAppender - Appends to a socket connection (also SSL).
  • S3FileAppender - Appends to a file, as in the FileAppender, and stores the file on Amazon S3.
  • S3BufferAppender - Appends to a cyclic buffer and stores it as a file on Amazon S3.

• Different Formatters for different needs
  • SimpleFormatter - Simple, fast and very small.
  • ConfigurableFormatter - A simple, but yet configurable formatter.
  • PatternFormatter - Decide exactly how you want to format your log messages. Inspired by the PatternLayout found in Log4j.
• High quality. We use use these tools to ensure that Microlog has high quality:
  • Unit tests (CLDCUnit combined with JUnit tests)
  • Code checks (FindBugs & Lint4j)

 

  As they say, the library can be adpated to different development stages:

1. Early development stage Use the ConsoleAppender and/or the RecordStoreAppender. Use the SimpleFormatter to start with. This makes it possible to run in the emulator and on the target device without any problems.
2. Main development stage Use the BluetoothSerialAppender to easily transfer the log directly to your PC. The PatternFormatter should be used to create better logging output, e.g. the thread name.
3. Field test by the developers Use the SyslogAppender class to log directly to a syslog server maintained by your team. The syslog daemon could be used to forward the logging messages, for example by sending e-mail.
4. Beta/Early access tests Use the MMSAppender to send logs when something critical has happened, e.g. when a FATAL or ERROR message has been logged. This could be sent directly to your bug reporting system and/or some mailing list for your development team. Or you could use the S3FileAppender to log directly into your Amazon S3 account.

Again, any comments from people using it is welcome.

Sun has released the new SDK for Java Mobile Development which is the successor of the Java Wireless Toolkit 2.5.2 and the Java Toolkit 1.0 for CDC. As they say " It integrates CLDC, CDC and Blu-ray Disc Java (BD-J) technology into one SDK".

The reported key features are:

• Integration with 3rd party emulators and Windows Mobile devices
• On-device deployment and on-device debugging
• CLDC/MIDP, CDC/FP/PBP/AGUI and BD-J integrated into one SDK
• New CLDC HotSpot Virtual Machine
• Optimized MSA 1.1 stack with extensions
• Profiling support
• BD-J support
• New development environment based on Netbeans Platform
• Lightweight UI Toolkit (LWUIT) integration
• Device search database integrated in SDK

Some of the new features are really appreciated.

For example the MSA 1.1 stack with extension includes the following new JSR:

• Mobile Sensor API (JSR 256)
• XML API for Java ME (JSR 280)
• Java Binding for the OpenGL ES API (JSR 239)

Also the integration with LWUIT is a very good features. This SDK is is the first developer's kit that comes with a built-in LWUIT library, resource manager and demo application.

And last but not least, the integrated device database which is a built-in WURFL database search engine with thousands of mobile devices. More than 8000 platforms are accessible using the database in the SDK.

I haven't tried the new SDK yet but I will do soon. If anyone has already tried it please post a comment.

Finally also LG has his own developer site where we can find documentation, emulators and SDK. Their phones were some of the most misterious devices on the market for the developers.

To see the new developer site click here