Chapter 9. Reflection

The Reflection API allows a Java program to inspect and manipulate itself; it comprises the java.lang.Class class and the java.lang.reflect package, which represents the members of a class with Method, Constructor, and Field objects.

Reflection can obtain information about a class and its members. This is the technique that the JavaBeans™ (see Chapter 15) introspection mechanism uses to determine the properties, events, and methods that are supported by a bean, for example. Reflection can also manipulate objects in Java. You can use the Field class to query and set the values of fields, the Method class to invoke methods, and the Constructor class to create new objects. The examples in this chapter demonstrate both object inspection and manipulation using the Reflection API.

In addition to the examples in this chapter, the Java Reflection API also features prominently in Examples Example 15-10 and Example 18-3.