Programming Wireless Devices with the Java2 Platform

Chapter 6. Mobile Information Device Profile

The Mobile Information Device Profile (MIDP) for the Java™ 2 Platform, Micro Edition (J2ME™) is an architecture and a set of Java libraries that create an open application environment for small, resource-constrained mobile information devices, or MIDs. Typical examples of MIDP target devices include cellular phones, two-way pagers, and wireless personal organizers. As summarized in Chapter 3, MIDP 2.0 devices typically fulfill the following minimum requirements:

• Memory:

  • 256 kilobytes of non-volatile memory for the MIDP components

  • 8 kilobytes of non-volatile memory for application-created persistent data

  • 128 kilobytes of volatile memory for the virtual machine runtime (for example, the object heap)

• Display:

  • Screen-size: 96x54

  • Display depth: 1-bit

  • Pixel shape (aspect ratio): approximately 1:1

• Input:

  • One or more of the following user-input mechanisms:

    • "one-handed keypad"

    • "two-handed keyboard"

    • touch screen

• Networking:

  • Two-way, wireless, possibly intermittent, with limited bandwidth

• Sound:

  • The ability to play tones, either via dedicated hardware or via software algorithm

Note that since MIDP runs on top of the J2ME Connected Limited Device Configuration (CLDC), the memory requirements of CLDC must be added to the minimum numbers shown above.