Configuring web applications programmatically

In addition to allowing us to configure web applications through annotations and through a web-fragment.xml, Servlet 3.0 also allows us to configure our web applications programmatically at runtime.

The ServletContext class has new methods to configure servlets, filters, and listeners programmatically. The following example illustrates how to configure a servlet programmatically at runtime, without resorting to the @WebServlet annotation or to XML:

package net.ensode.javaee8book.servlet; 
 
import javax.servlet.ServletContext; 
import javax.servlet.ServletContextEvent; 
import javax.servlet.ServletContextListener; 
import javax.servlet.ServletException; 
import javax.servlet.ServletRegistration; 
import javax.servlet.annotation.WebListener; 
 
@WebListener() 
public class ServletContextListenerImpl implements 
        ServletContextListener...