一点点迷惑 about org.apache.struts.taglib.TagUtils

[coaa]

该类的方法:public java.lang.Object lookup(javax.servlet.jsp.PageContext pageContext,java.lang.String name,java.lang.String scopeName)throws javax.servlet.jsp.JspException
有下面的一些说明.
Locate and return the specified bean, from an optionally specified scope,
^^^^^^^^^^^^^^^指定的bean是java文件么?那些java文件才能被叫做bean,是从功能上划分的吗?
in the specified page context. If no such bean is found, return null instead. If an exception is thrown, it will have already been saved via a call to saveException().