Convention Over Configuration

Apache Tapestry follows Convention over Configuration in every aspect of programming. Every feature of the framework does have a sensible default convention.

For example, as we learned in the Project Layout chapter, all pages need to be placed in the /src/main/java/«package_path»/pages/ folder to be considered as Tapestry Pages.
In another sense, there is no need configure a particular Java Class as Tapestry Pages. It is enough to place the class in a pre-defined location. In some cases, it is odd to follow the default convention of Tapestry.
For example, Tapestry component can have a method setupRender which will be fired at the start the rendering phase. A developer may want to use their own opiniated name, say initializeValue. In this situation, Tapestry provides Annotation to override the conventions as shown in the following code block.

void setupRender() { 
   // initialize component 
}  
@SetupRender 
void initializeValue() { 
   // initialize component 
}

Both ways of programming are valid in Tapestry. In short, Tapestry's default configuration is quite minimal. Only the Apache Tapestry Filter (Java Servlet Filter) needs to be configured in the “Web.xml” for the proper working of the application.
Tapestry provides one another way to configure application and it is called as the AppModule.java.