Reflection 是Java被视为动态（或准动态）语言的一个关键性质。这个机制允许程序在运行时透过Reflection APIs取得任何一个已知名称的class的内部信息，包括其modifiers（诸如public, static 等等）、superclass（例如Object）、实现之interfaces（例如Cloneable），也包括fields和methods的所有信息，并可于运行时改变fields内容或唤起methods。本文借由实例，大面积示范Reflection APIs。-Reflection is Java is seen as a critical nature of the dynamic (or quasi-dynamic) languages​ ​ . This mechanism allows the program to obtain internal information of a known name of the class, including its modifiers (such as public, static, and so on) at run time through the Reflection APIs for the superclass (for example, Object) implementations of the interfaces (such as Cloneable), also include all the information in the fields and methods, and can change at runtime the fields content or to arouse methods. This article by by the instance, a large area demonstration Reflection APIs.