The word security has many meanings; the need to hide personal information, user authentication and data encryption are all subjects related to the security topic. We can think, for instance, about what would happen if we download a malign midlet that, at a certain time, starts sending SMS messages to a specific phone number giving away personal information about our agenda or other data stored in our device. In that case the damage affects both privacy and money. In this module we’ll talk about what the MIDP 2.0 specification tells us about security, and we’ll learn how to sign a MIDlet Suite to grant the execution of operations that usually the midlet may only run after a user confirmation. Then we’ll create a simple application and we’ll observe how it runs: our goal is to compare the behavior of a signed and of an unsigned application. Read more »

After reading the first four modules we are now able to create a MIDlet managing its own GUI using HIGH and LOW level APIs. In this module we’ll talk about memory management, a very important feature of small device applications. We’ll deal with two types of memory:

- Volatile memory
- Non-volatile memory (persistent memory) Read more »

In the third module we studied how to create midlet user interfaces using the high level API. We learned that, using that API, we can develop portable GUIs delegating to the underlying device the creation of specific widgets such as Lists, TextFields and so on. We stated that if we need more control over the device’s screen we need to use a different API – called Low Level API – which allows us to have complete control over the device at the cost of a portability loss. For instance, if we have to build a List using the High Level API we just create a List instance and then we add it to a Form. If we want the same result using the Low Level API, we have to manage list items and draw them on the screen using graphic primitives: lines, curves and rectangles must be painted using specific methods. In this case, of course, we need to know the screen dimension, then we have to choose the colors, draw list items and so on. Read more »

In the first two modules we dealt with MIDP 2.0 fundamental concepts and we started programming a simple MIDlet. We talked about the midlet-device interaction lifecycle and we developed a simple application. In this module we’ll dive into MIDP 2.0 programming, beginning with the high level API for midlet GUI creation. This is an important module since it covers the fundamental widgets we can use in a portable midlet application. It’ll be shown how to use these widgets by creating a simple midlet which simulates a user registration. Read more »

In the first module we introduced MIDP2.0 fundamental concepts. We talked about Configuration, Profile and Optional Packages. In this module we start programming our first midlet and studing the midlet lifecycle in detail. We’ll end with some useful methods in order to create a simple Alert MIDlet. From now on, with midlet we’ll refer to the application and with MIDlet (with uppercase MID)we’ll refer to the MIDlet class.

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This is the first module of a guide about MIDP programming with the J2ME environment. In this first part we’ll introduce configuration and profile, fundamental concepts that are very important for understanding MIDP. After that we’ll install the WTK 2.5 that is the toolkit for creating, developing and testing your application to be used on real MIDP 2.0 devices.

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This micro guide is the first of a colection dedicated to c++ dvelopers that want to prodcuce a more robust code.
These suggestions are only a quick guide based on our experience as mobile developers.

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