J2ME divides all embedded devices into two types: one is a embedded device (PDA, mobile phone, etc.) of the calculation function, and the power supply is also limited; the other is relatively better, and the power supply is relatively More adequate embedded devices (air-conditioner, refrigerator, set-top box, etc.).
From the above two distinction, Java introduced
Configuration concept, and then define the above operational function, limited power limited device definition in Connected Limited Device Configuration
CLDC) The specifications; the other device specifically is Connected Device Configuration.
CDC) Specifications. That is, J2ME first uses all embedded devices.
The concept of Configuration is divided into two abstract types.
Here you can
Configuration is used as a specification for the two type embedded devices, and these specifications define these devices at least in accordance with specifications, power supply capacity, memory size, etc., and also define a set of executed in these devices. The category function library that the Java program can use, the category function library defined in these specifications is a subset of Java core categories and an expansion category that is consistent with the type of state device characteristics. Alterate
CLDC specification, the core category that can be supported is java.lang. *, Java.io. *, Java.util. *, And the expansion category can support Java.microedition.IO. *.
Different major
After configuration, J2ME then defines
PROFILE concept.
Profile is architecture
Specifications above Configuration. Whose reason
The concept of Profile is to make it easier to distinguish how the Java program is developed on various embedded devices. Therefore, in PROFILE defines the expansion category that is very relevant to a particular embedded device, how the Java program is presented in the user interface of the user interface of various embedded devices is defined.
In front of the Profile. The expansion category defined in Profile is also based on the underlying
The core category defined in Configuration is established.
According to some
The Java program written by the PROFILE specification can directly call the expansion categories defined in the profile, or they can be used directly.
The core category set and expansion category defined by the Configuration.
Currently
There are two kinds of Profile derived from CLDC, one is Handheld Profile, mostly on the PDA; and another is the Mobile Information Device Profile.
MIDP), this
PROFILE is a mobile device for a mobile device for a mobile device.
Embedded Java and Personal Java do not seem to be included in two
Under any of the Configuration, they are also classified in the category of J2ME, and also derived the real-time Spectation for Java of Java. Embedded Java and Personal Java will slowly replaced by the architecture in Profile on the CDC. In Personal Java, its specifications are compatible with the Specifications of the Personal Profile. The main reason why Embedded Java and Personal Java is mainly used is that there have been a lot of works in the market, so the Personal Java will continue to evolve in the short term, and it is still unable to classify J2ME.
Under Profile.
A minimum configuration requirement for a particular type of embedded device is defined in PROFILE.
Profile Construction
What is the meaning of Configuration?
Equipment demand specified in PROFILE is impossible to
CONFIGURATION is still low. At the same time, in Profile, the relevant needs of the display function, network function, and power consumption capacity will be higher than in Configuration. Under the bottom is some
PROFILE Equipment Requirements:
Equipped with / Profile Foundation Profile Personal Profile MIDP
Ram
At least 512K
At least 1 MB
RAM and ROM are at least 512K
ROM
At least 1024K
At least 2.5 MB
RAM and ROM are at least 512K
power supply
Not limited
Not limited
Usually used battery, limited power supply
Network connection capability
Partial function
Partial function
Wireless communication capabilities with low frequency width
other
Have additional RAM or ROM supply execution
Have additional RAM or ROM supply execution
There is an additional RAM or ROM supply execution and storage information
