Undertow allows to deploy duplicated URLs on Servlets

A deployment with two Servlets, each one with the same mapping: "/test2". The deployment finishes correctly. When accessing the path, just one Servlet answers, without errors.

A deployment with two Servlets, with the following paths:

• /test1
• test1

The deployment succeeds, but a 500 error is shown when trying to access any page (not just /test1). See also WFLY-7658.

Servlet Spec 3.1 says in point 12.2:

If the effective web.xml (after merging information from fragments and annotations) contains any url-patterns that are mapped to multiple servlets then the deployment must fail.