Can you ever think of writing a Java program without a class ? I know the answer is ‘NO’. As a class is the heart of the java program , it is always good to know about the in and out of the class. Java provides a very ordinary(but strong enough) API to know more about java classes , methods and fields. This API is known as Java Reflection API. Don’t you wonder how Eclipse IDE gives you the Auto complete feature ? How web application deployment descriptor (web.xml for tomcat) works ? The basic answer is REFLECTION. Have a look.