|
The Java Class Library (JCL) is a set of dynamically loadable libraries that Java applications can call at run time. Because the Java Platform is not dependent on a specific operating system, applications cannot rely on any of the platform-native libraries. Instead, the Java Platform provides a comprehensive set of standard class libraries, containing the functions common to modern operating systems. JCL serves three purposes within the Java Platform: * Like other standard code libraries, they provide the programmer a well-known set of useful facilities, such as container classes and regular expression processing. * The library provides an abstract interface to tasks that would normally depend heavily on the hardware and operating system, such as network access and file access. * Some underlying platforms may not support all of the features a Java application expects. In these cases, the library implementation can either emulate those features or provide a consistent way to check for the presence of a specific feature. ==Implementation and configuration== JCL is almost entirely written in Java, except for the parts that need direct access to the hardware and operating system (such as for I/O, or bitmap graphics). The classes that give access to these functions commonly use Java Native Interface wrappers to access operating system APIs. Almost all of JCL is stored in a single Java archive file called "rt.jar", which is provided with JRE and JDK distributions. The Java Class Library (rt.jar) is located in the default bootstrap classpath,〔(How Classes are Found )〕 and does not have to appear in the classpath declared for the application. The runtime uses the bootstrap class loader to find the JCL. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Java Class Library」の詳細全文を読む スポンサード リンク
|