1. J2ME architecture detailed explanation
2 Profile
2 Configuration
2 kVM (CVM)
2 host overcast system
1) Configuration ----- Because there is a big difference between the hardware platform supporting J2ME
I. There is a relatively high-end device, such as a TV set-top box, network TV, etc. ----- is relatively preferred, and relatively sufficient embedded devices in power supply
II. There are also low-end devices, such as mobile phones, pagers, PDAs, etc. ----- is an embedded device that is limited in operation.
III. In order to meet the development requirements of the above two major hardware, J2ME specifies the Configuration concept for hardware data processing power, storage capacity, network connection capabilities, etc., limited, limited, limited, limited power, limited power, limited electricity Among the Connected Limited Device Configuration (Configured CLDC) specifications, the Java virtual machine used by CLDC is called KVM (kiloby virtual machine).
The other device specifically specifically for the Connected Device Configuration (Configure CDC) specification. And the Java virtual machine used by the CDC is called CVM.
V. CDC, CLDC is only a basic set of functions for the most common configuration in various devices.
2) Profile ----- Although there is a CDC, CLDC, there is still a big difference between different devices in practical applications. Thus, J2ME defines the concept of Profile on the basis of Configuration. Profile is a norm and API for a certain type of device. Here are two examples:
I. Application of mobile phone ----- J2ME defines a specialized Profile-MIDP (Mobile Information Device Profile)
II. Developed in PDA ----- J2ME also defines a PDAP (PDA PROFILE).
3) CLDC is a subset of CDC, because the resource constraint does not include all J2SE classes, and the CDC library also includes several new interfaces and classes for CDC.
4) Summary ----- Only a Configuration above Virtual Machine, and there are several profiles on the Configuration, so that it can effectively construct a perfect operating environment for a variety of different devices.
2. Some specific contents in the most widely used MIDP specification (architecture)
2 MID Profile
2 CLDC Core Libraries
2 kVM
2 host overcast system
1) API part
I. User Interface Support: Provided by the class package is javax.microedition.lcdui
II. Network Support: Provided by the class package is javax.microedition.io
III. Data Continuous Storage Support: Provided by a class package is javax.microedition.rms
IV. Other Expert Processing and Timer and other class support
2) Hardware part
I. Memory: 128KB stable memory for MIDP components; 8KB stable memory for data continuous storage; 32KB stable memory for virtual machines
II. Display: The screen size is 95 × 54 pixels, 1 bit color depth, the screen aspect ratio is approximately 1: 1iii. Enter the device: keyboard, touch screen or both
IV. Network: Provides two-way, wireless, but may be intermittent communication functions in the case of limited bandwidth.
