Eclipse - How can I change a 'Project Facet' from Tomcat 6 to Tomcat 5.5?

Question

This is kind of hacking eclipse and you can get into trouble doing this but this should work:

Open the navigator view and find that there is a .settings folder under your project expand it and then open the file: org.eclipse.wst.common.project.facet.core.xml you should see a line that says: <installed facet="jst.web" version="2.5"/> Change that to 2.4 and save.

Just make sure that your project isn't using anything specific for 2.5 and you should be good.

Also check your web.xml has the correct configuration:

<web-app version="2.4" 
        xmlns="http://java.sun.com/xml/ns/j2ee" 
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

This may be old but I tried and found the following in eclipse Galilio.

Open the navigator view and find that there is a .settings folder under your project expand it and then open the file: org.eclipse.wst.common.project.facet.core.Delete the content of this file and right click on the project and click on properties. Go to Project Facats in the popup window there you can click on runtime tabs and convert your project to the new facet you want.

if you are using Maven, then shutdown eclipse, then type >mvn eclipse:eclipse -Dwtpversion=2.0, and restart the eclipse.