Difference between Interceptors and Filters - Is this right?

Question

I'm researching this so that I can respond better in interviews. I've been searching around for a clear and concise answer.

So far, and by all means correct me if I am wrong or lacking in detail:

1. Filters are part of the Servlet API, Interceptors are Struts 2. (Seems obvious though)
2. The Interceptor stack fires on requests in a configured package while filters only apply to their mapped URLs.
3. Interceptors can be configured to execute or not depending on specific target action methods via excludeMethods and includeMethods while Filters lack this feature.
4. Filters are an implementation of the Intercepting Filter pattern while Interceptors are of the Interceptor pattern.

Does this seem like an accurate and complete answer? Should I add or correct anything? What about threading issues / differences?

Answer 1

Filters are from Servlet API and Interceptors are from Struts 2 , Difference comes when we talk about web applications and enterprise apps, filter is used only in web applications whereas interceptor can be used with web as well as enterprise applications. Life cycle methods of both, also differs.

The interceptor stack fires on every request. filters only apply to the urls for which they are defined. you use one or the other depending on need. Lets say you need to verify a cookie is present for every request. Use an interceptor. Lets say that you need to pop up an external app on some requests (driven by a url), use a filter.