Targeting MIDP mobile devices like cell phones and PDAs, the MIDP 1.0 specification provided a starting point for MIDlets (MIDP application packages). But basic security and user-interface support limited MIDlet use. MIDP 2.0 solves these problems by providing support for MIDlet authentication, improved network connectivity, and better user-interface support such as sound and graphics. MIDP is designed to run on top of the Connected Limited Device Configuration (CLDC).
The CLDC is just one part of J2ME (Java 2 Micro Edition). It provides minimal Java support and can be extended by adding profiles such as MIDP. MIDP 2.0 adds a number of packages that enable network access, user interface, device control, and security. Though MIDP 1.0 included much of these capabilities, it wasn't as functional. It also lacked the security features available in MIDP 2.0.
To keep MIDP 1.0 systems secure, designers had to minimize access to system services. This sandbox approach to security is good but limiting. MIDP 2.0 can give trusted MIDlets access to more services. For example, a MIDP 1.0 MIDlet couldn't access a remote server while a MIDP 2.0 MIDlet may if it has the proper authorization. This enhanced security is handled via digital signatures and the Public Key Infrastructure (PKI) support. A device will authenticate MIDlet signatures prior to providing access to services.
The added security features makes the new HTTPS support possible. MIDP 1.0 only offered HTTP links. Secure links to remote servers is necessary for a range of applications from banking to game play.
BUILDING GAME MIDLETS Game developers are very interested in moving from MIDP 1.0 to MIDP 2.0. Joe Sengir, senior programmer at Sennari Inc. (www.sennarigames.com), says that the improved LCD support and new sound capability on MIDP 2.0 will greatly enhance the games that can be delivered. The sound support is a subset of the Mobile Media API. The ability to access palettes and image arrays directly will bring games to a whole new level. Of course, this means the platforms will have to support MIDP 2.0.Another good reason to hasten the migration to MIDP 2.0 is the form enhancements. The form support is part of the LCD user-interface package. It includes new layout features and minimum and preferred sizes for controls. This is important for running MIDlets on platforms that have different screen characteristics.
The MIDP 2.0 specification can be found at www.jsr.com.
| MIDP 2.0 PACKAGES | |
| io | Network I/O |
| lcdui | LCD User Interface |
| lcdui.game | LCD User Interface for Games |
| media | Media |
| media.control | Media Control |
| midlet | MIDP application packages |
| pki | X.509 Public Key Infrastructure |
| rms | Record management system |