《深入理解java虚拟机》学习笔记--第六章：类文件结构

虚拟机的平台无关和语言无关性：

（1）虚拟机可以运行在各种平台上，这些虚拟机都可以在如何执行一种平台无关的字节码，实现了“一次编写，到处运行”的目的。

（2）除了平台无关，虚拟机的另一个特点是语言无关，也就是说不仅是java语言，其他语言也可以运行在java虚拟机上。即不同语言的程序可以通过各类语言的编译器把程序编译成Class（字节码）文件，从而顺利在java虚拟机上运行。

Class类文件的结构：

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Class文件是一组以8为字节为基础单位的二进制流，各数据项目按照严格的顺序紧凑的排列在Class文件中，中间没有添加任何的分隔符，这就是的整个Class文件中存储的内容几乎都是程序运行时的必要数据。当遇到需要占用8为字节以上空间的数据项时，会按照高位在前的方式分割为若干个8为字节进行存储。