Which the three are true about servlet filters？（）

• A、 A filter must implement the destroy method
• B、 A filter must implement the doFilter method
• C、 A servlet may have multiple filters associated with it
• D、 A servlet that is to have a filter applied to it must implement the javax.servlet.FilterChain  interface
• E、 A filter that is part of a filter chain passes control to the next filter in the chain by invoking the filterChain forward method
• F、 For each  element in the web application deployment descriptor， multiple instances of a filter may be created by the web container