What is a ZK component

Each UI object in ZK consists of a component and a widget.

Component

A component is a Java object running at the server which represents a UI object which can be manipulated by a Java application. A component has all the behavior of a UI object except it has no visual part.

Widget

A widget is a JavaScript object running at the client. This object represents the UI object which interacts with the user. Therefore, a widget usually has a visual appearance, and handles events happening at the client.

Having established that there are two parts to a ZK Component one needs to explore how these parts interact with one another to form a fully interactive user experience.