专门用来操作java 字节码文件的开源框架，可以像sax，dom解析xml一样，解析class文件，并对class文件进行操作，hibernate等开源框架都是用它-Designed to operate in the open source java fr a mework for bytecode file, can be like sax, dom, like xml parsing, parsing class files, and file class action, hibernat