赵帮辉中英文翻译(3)

类的构成包括成员变量/对象与成员方法，这样将相关的数据与函数包装在一起，同其他的类相区分，就是封装。显然，避免了面向过程语言的平行缺陷，说明了类和成员之间的所属关系。进一步地，可以限制类的成员在外部的可见性，那么就将封装体现得更完美。

2、继承

当一种事物甲完全是另一种事物乙的特例，那么，一般地，类甲只是比类乙多出一些成员变量/对象与成员方法，称为类甲继承类乙，类甲称为（类乙的）子类，类乙称为（类甲的）父类。

父类也称为基类、超类，子类也称为导出类、派生类。

显然编写子类就没有必要重复书写父类中乙有的代码部分，这是OOP中最典型的代码重用。

3、多态

多态表示一个类的某种行为存在多种实现版本。简单的情况是在一个类中，给出多种不同的实现，复杂的情况是在多个子类中各自给出不同的实现。

*1.5 Java与C++的差异 1.6本章小结 习题

1．解释Java语言的三种平台。

2．解释支撑Java语言目标的三种主要技术（自查资料完善）。

3．关于面向对象与面向过程的不同，从问题理解和问题表示两种角度，按照个人的理解和认识，例示其不同的地方

Overview of Java language

Java, from Sun Microsystems, launched in May 1995 of the Java programming language and Java in general. Hot Java implementation with Java browser (supporting Java applet) shows the charm of Java: cross-platform, dynamic Web, Internet computing. Since then, Java is widely accepted and promoted the rapid development of Web, popular browsers now support Java applet. Platform

Java platform by the Java Virtual Machine (Java Virtual Machine) and Java application programming interfaces (Application Programming Interface, referred to as API) composition. Java application programming interface for Java applications independent of the operating system of a standard interface, can be divided into the basic part and extension. In the hardware or operating system platform, after installing a Java platform, Java applications can run. Embedded Java platform now has almost all the operating systems. This Java program can only compile it once, you can run a variety of systems. Java application programming interface has been developed from a 1.1x version to version 1.2. The Java platform is based on the commonly used Java1.5, a recent version Java1.7.