O'Reilly logo

Head First Servlets and JSP, 2nd Edition by Bert Bates, Bryan Basham, Kathy Sierra

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

You can’t use servlet init parameters until the servlet is initialized

You already saw that your servlet inherits getServletConfig(), so you can call that from any method in your servlet to get a reference to a ServletConfig. Once you have a ServletConfig reference, you can call getInitParameter(). But remember, you can’t call it from your constructor! That’s too early in the servlet’s life... it won’t have its full servletness until the Container calls init().

image with no caption

When the Container initializes a servlet, it makes a unique ServletConfig for the servlet.

The Container “reads” the servlet init parameters from the DD and gives them to the ServletConfig, then passes the ServletConfig to the servlet’s init() method.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required