I want to add a servlet to Alfesco, and that requires a change to the web.xml file. Can you make changes to web.xml via an AMP installing into alfresco.war?
You can't make changes to the web.xml but I believe you can replace it using an AMP.
Be aware though this is not upgrade proof as you will need to provide the whole web.xml in your AMP, if it changes from release to release you will have to ensure your AMP uses the latest web.xml.