ERROR - Error 404: javax.servlet.UnavailableException: SRVE0201E: Servlet : not a servlet class

Problem

00000045 WebExtensionP W Servlet is currently unavailable: SRVE0201E: Servlet : not a servlet class

Cause
  
This is due to a jar having javax.servlet.Servlet in web-inf/lib as if you have any jar file that has
javax.servlet.Servlet (Eg: geronimo-j2ee_1.4_spec-1.0.jar or Servlet-api-2.3.jar) as part of web-inf/lib in your war file then your app inherits the servlet api from the jar that are in web-inf/lib and not the j2ee.jar provided by server.


Resolution

  • set the Parent last in the class loading policy for the application and module as well .
  • Remove the jars having javax.servlet.Servlet from the project.