You can extend your WebForm applications function by including JavaBeans.
JavaBeans are program units that are written in Java and conform to the JavaBean specification. JavaBeans can be integrated with your application to perform specialized functions that augment your forms capabilities.
See the Extending Your Application with Pluggable Java Components for more information about the value and characteristics of JavaBeans.
To have the JavaBean integrate correctly with your application, you could use the Enhanced JavaBean support Features, or you must provide a container for it. This container (sometimes also called a wrapper) must implement a WebForms-defined interface, called the IView interface.
If the JavaBean is also going to communicate with the form during runtime, then your container must also extend the VBean class. (The VBean class implements the IView interface.) By extending the VBean class, your container can take advantage of the CustomListener and can dispatch custom events.
In the constructor of the container, you instantiate the JavaBean. Your container can implement various event listeners, and you can register the container as a listener for various events handled by the JavaBean. Also, you can register properties and set the properties in the handler that is passed into the init() method. These properties can be shared with the form.
How to Add JavaBeans by Writing Your Own Java Code
Including a JavaBean and Custom Controls