What is J2ME Wireless Toolkit?

[Calan]

I have been just told that, the Sun Java Wireless Toolkit (previously known as Java 2 Platform, Micro Edition (J2ME) Wireless Toolkit) is a state-of-the-art toolbox for budding wireless applications that are based on J2ME's Connected Limited Device Configuration (CLDC) and Mobile Information Device Profile (MIDP), and premeditated to run on cell phones, mainstream personal digital assistants, and supplementary small mobile devices. I am not having more knowledge than this. So thought to take some help. Please provide some information about J2ME Wireless Toolkit? Also tell me what are tools used for it?!

[Efigenio]

In order to develop Java applications for mobile terminals, you can start to download the J2ME Wireless Toolkit (WTK), the development environment offered by Sun's full compiler and emulators currently in version 2.2. Once installed, you can click on "KToolbar" found in the group of the J2ME Wireless Toolkit "Start" in Windows (there is also a Linux version). For the drafting of the code you can use a common development IDE like Eclipse or Net Beans Mobility Pack (which plug-in and native support for developing J2ME). The WTK can be integrated that will allow us then to make the code unreadable and have smaller size for our applications. You can install Proguard, for example, by copying the folder "bin" directory to install the Toolkit.

[Osman84]

J2ME application is essentially composed of two files, respectively extension "jad" and "jar". The jar is the actual application, while the jad (Java Application Descriptor) contains information useful for installation from the terminal and other data that characterize the midlet. In this first example, we realize an application that reads some parameters from the jad. Click the "New Project", the WTK, and insert the required information: the name of the project (eg MyMidlet) and the main class (including package) of our application ( mymidlet.MyMidlet ). On the next screen, if you click on the tab "Required", we can see some of the information required to be present in the jad file, we find, for example:

• MIDlet-Jar-Size: size of the jar files (managed by WTK);
• MIDlet-Jar-URL: The url from which to download the application in case of delivery via OTA (if, instead, we use other transfer methods, such as Bluetooth or serial cable, this parameter can contain only the name of the jar).

Then click "Ok" at the bottom. At this point, in the "apps" directory of the WTK, we find a folder "MyMidlet" which in turn contains the following dir:

• bin : where to find jar and jad at the end of construction;
• lib : For third-party libraries needed for our application;
• res : for images and resource files in general;
• src : to the sources.

J2ME applications are handled by a manager, called Java Application Manager (JAM), which determines the different states of the midlet by invoking the appropriate methods of the main class.

[Quattro]

The explosion of the market for mobile handsets, PDAs and mobile phones, has meant that Sun pushed even on those platforms with technology known as Java Micro Edition or J2ME. The technological challenge was to define a set of APIs, to make available to developers, who fulfilled the minimum availability of items:

• have limited processing capability;
• have limited storage capacity;
• have small screens (sometimes not in color) and with little resolution.

The market supply is also very diverse and has several terminals in terms of functionality and technical characteristics (consider, for example, the difference in computing power and display of a mobile phone and a PDA). To support such a wide range of terminals, Sun introduced the concept of Configuration that can identify with the definition of the core library (core) and the characteristics of a Java Virtual Machine (JVM) that resides on a system with certain capabilities.

[T0tal L0$$]

To support such a wide range of terminals, Sun introduced the concept of Configuration that can identify with the definition of the core library (core) and the characteristics of a Java Virtual Machine (JVM) that resides on a system with certain capabilities.

In particular we define two different Configuration:

• Connected Device Configuration (CDC) in its current version (1.1) is present in terminals with the following minimum requirements:
  
  • 512 KB of available RAM
  • 256 kbytes of memory to run Java applications
  • Possibly continuous network connectivity and broadband
• Connected Limited Device Configuration (CLDC) and the current version (1.1) is present in terminals with the following minimum requirements:
  
  • 192 kb of memory to run Java applications
  • A 16-or 32-bit processor
  • Low power consumption (usually caused by batteries)
  • Network connectivity (usually wireless) access with limited bandwidth and intermittent.

From now on our focus will be on CLDC, whose particular JVM was called KVM (K Virtual Machine). It was then necessary to make this platform even more flexible by introducing the concept of profiles representing the set of libraries that enable the management of user interfaces, capture and handling events, persistent storage, connections, and management timer device in a specific type.