By default websphere application server (WAS) 6.1 (maybe 6.x) has the J2EE filters disabled.
Don’t know why. Don’t ask it to me. I only know that the custom rewrite/redirect I made in my J2EE filter didn’t work until I told middleware office to set a websphere custom property.
The property to set is com.ibm.ws.webcontainer.invokefilterscompatibility and has to be set to true. You can find where to set it under the websphere administration console following this path Application Servers -> <server> -> Web Container Settings -> Web Container -> Custom Properties.
Easy once you know what to do. 🙂