Preface, it may be messy ~~~~~
1.1When writing a program in Java, Sun will use the java standard class library provided by Sun. It is a core class library (core class) consisting of various packages, that is, Java. *, and extended class, that is, javax. *;
1.2Cldc and MIDP
ClDC: The configuration concept exists in j2's, which basically refers to the hardware capability (CPU, memory, etc.), respectively cldc (connected limited device configuration can be connected to the outside world, with limited resources) CDC (connected Device Configuration resources are unlimited). The supported libraries include Java. lang. * Java. io. * Java. util. * javax. microedition. io. *;
MidP: There is also a profile (feature) above configuration. My understanding is that some methods for special devices are expanded based on configuration, including mobile information device profile (MIDP ), pointer specification for mobile devices.
1.3MIDlet and MIDlet suite
MIDlet: The basic unit of an executable application, except that it inherits from javax. microedition. MIDlet. MIDlet also includes a set of resource files (not all of which are resource files) that can be smoothly executed by this class. MIDlet suite: A collection composed of many midlets, also known as the MIDP application. a midp application can contain many midlets, but generally only one.
1.4Jar and Jad a complete MIDP application, composed of a JAD file and a jar file.
Jad: A text file (description file) that describes the basic information of the MIDP application. It corresponds to jar through Jad.
Jar: Contains the MIDP Application Files (ZIP compression format), including class files and resource files, and a configuration file (manifest. mf is used to describe the basic information of the application ).
Note:If the description file or the configuration file contains non-ASCII code-defined text, the default format is utf8 (if it is MIDP for Palm, it must use ASCII Unicode ), currently, the j2's development tools will automatically convert the Chinese we entered into the utf8 encoding format and store it in the description file or list file.
1.5The class file in the basic function jar of the MIDP application can be called by all the MIDlet in the same class, and the resource file can be called through Java. lang. class. getresourceasstream (). The content of the description file and list file can be accessed through Java. microedition. MIDlet. MIDlet. getappproperty () is obtained. The platform features can be obtained through Java. lang. system. getproperty. Note: a URL is required when getresourceasstream is used. It is best to start with "/" and "/" indicates the root directory in the jar file. In addition, the class file cannot be accessed as a resource.
