J2ME Learning Notes (2) Source 1. J2ME Architecture Detailed 2 Profile 2 Configuration 2 KVM (CVM) 2 Host Operating 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 a relatively better calculation capacity, and relatively sufficient embedded device II on power supply is relatively low. There are also relatively low-end devices, for example : Mobile Phone, Pager, PDA, etc. ----- is a limited operation of the calculation function, and the power supply is also limited. 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 phones ----- J2ME defines a dedicated Profile-MIDP (Mobile Information Device Profile II. Developed in PDA ----- J2ME also defined 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 Operating System
1) API section I. User interface support: Provided package package is javax.microedition.lcdui II. Network support: Provided package package is javax.microedition.io III. Data Continuous Storage Support: Provided package package is Javax.microedition.rmsi IV. Other exceptions and Timer's support
