说明：  分别介绍了JAVA的基本数据类型，语句，类，对象，接口，内部类，异常处理，字符串，实用类，AWT组件，多线程，输入输出流，网络编程，JAVAApplet，数据结构类，JDBC，JavaSwing等内容。
(JAVA introduced the basic data types, statements, classes, objects, interfaces, inner classes, exception handling, strings, practical classes, AWT components, multi-threading, input and output stream, network programming, JAVAApplet, the data structure class , JDBC, JavaSwing and so on.)