Get rid of "The value for annotation attribute must be a constant expression" message

The value for an annotation must be a compile time constant, so there is no simple way of doing what you are trying to do.

See also here: How to supply value to an annotation from a Constant java

It is possible to use some compile time tools (ant, maven?) to config it if the value is known before you try to run the program.

This is what a constant expression in Java looks like:

package com.mycompany.mypackage;

public class MyLinks {
  // constant expression
  public static final String GUESTBOOK_URL = "/guestbook";
}

You can use it with annotations as following:

import com.mycompany.mypackage.MyLinks;

@WebServlet(urlPatterns = {MyLinks.GUESTBOOK_URL})
public class GuestbookServlet extends HttpServlet {
  // ...
}