Initializes the properties (aka. members) and custom-attributes based on what are defined in the component definition.
This method is invoked automatically if a component is created by evaluating a ZUML page, i.e., if it is specified as an element of a ZUML page.
On the other hand, if it is created manually (by program), developer might choose to invoke this method or not, depending whether he wants to initializes the component with the properties and custom-attributes defined in the ZUML page ( {@link org.zkoss.zk.ui.metainfo.PageDefinition}) and the language definition ( {@link org.zkoss.zk.ui.metainfo.LanguageDefinition}).