J2ME

Although mobile devices provide an ideal method for users to access the Internet in real-time and at any place, they do have intrinsic constraints dealing with the complexities of Internet protocols and standards.

These limitations include:

• Bandwidth Restrictions: Although 3G technology promises to have great potential and bring many new wireless applications into our lives, the speed of today's dominant wireless data networks (CDMA and 2.5G GPRS) continue to hinder the development of wireless data services because they still simply take too long to download a typical PC application.
• CPU Limitation: Embedded processors are generally optimized for battery consumption and are not well suited for computationally intensive tasks.
• Memory Constraints: Embedded devices typically have very limited built-in memories compared with desktop machines. Embedded applications must be developed with this in mind to minimize memory usage and improve functionality on embedded devices.
• Compatibilities: Unlike personal PCs, wireless devices tend to be much more diversified with different capabilities - and different standards. Applications developed for one device are frequently unusable on other mobile devices. This creates barriers for wireless application developers, forcing them to write the same application multiple times for different devices.
• Device Configurations: Mobiles devices employ many different design paradigms with various input methods, screen sizes, color capabilities, and character sets. Applications must be designed with these considerations in mind to be fully functional on the target device.

Java-based architecture offers an alternative solution for mobile devices with these limitations. Java provides the ideal platform for developing complex mobile applications that can be deployed both on the wireless device and the application server, thus being independent of any host hardware and operation system limitations. However, the standard Java API's and virtual machines (VM) are feature rich but simply too big and slow to run directly on resource-constrained mobile devices. Small runtime memory footprints and fast execution speeds prove essential for mobile applications. This is why US based Sun Microsystems created a small-footprint edition of Java: Java 2 Platform, Micro Edition (J2ME) and an ultra compact Java virtual machine or KVM. CSOFT's VMxp is such type of KVM.

J2ME consists of two parts: configurations and profiles. The Connected Limited Device Configuration (CLDC) and Mobile Information Device Profile (MIDP) combination is designed specially for mobile devices with limited resources, such as wireless phones and PDA's. CLDC provides class libraries to support a limited set of Java core language application programming interfaces (APIs); MIDP adds classes for GUI components, networking, and persistent storage. CLDC and MIDP work together to provide a complete development and runtime environment for mobile devices. Each MIDP-supported mobile device has a MIDP VM that can run compiled MIDP byte code, allowing J2ME applications to run on all MIDP devices.

J2ME applications are real programs that can handle interactive user interfaces, manipulate data, and allow offline user interaction. In contrast with platform-native applications, J2ME applications are portable across diverse mobile platforms and can be deployed over the Internet. J2ME developers can take advantage of Java's sound object-oriented design and many third-party libraries or components that are currently available for the Java platform.

For more information about CSOFT's wireless application solutions, please click here.