tomcat-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From bugzi...@apache.org
Subject DO NOT REPLY [Bug 8705] - SessionListener should extend EventListener
Date Wed, 01 May 2002 20:06:43 GMT
DO NOT REPLY TO THIS EMAIL, BUT PLEASE POST YOUR BUG 
RELATED COMMENTS THROUGH THE WEB INTERFACE AVAILABLE AT
<http://nagoya.apache.org/bugzilla/show_bug.cgi?id=8705>.
ANY REPLY MADE TO THIS MESSAGE WILL NOT BE COLLECTED AND 
INSERTED IN THE BUG DATABASE.

http://nagoya.apache.org/bugzilla/show_bug.cgi?id=8705

SessionListener should extend EventListener





------- Additional Comments From craig.mcclanahan@sun.com  2002-05-01 20:06 -------
We ran into this case in one of the proposed changes to Servlet 2.3, which added
FilterConfig.  Conceptually, it made sense to abstract out the common features
of FilterConfig and the existing ServletConfig interfaces into a new Config
interface that both would inherit from.  Alas, when you do that, code compiled
against the "old" version cannot run against implementations compiled against
the "new" version -- and vice versa.  So, we had to back away from doing this.

The reason this happens is that the compiler remembers the whole inheritance
tree at compile time, and the JVM uses that at runtime as part of the matching
criteria to see if the class you are requesting is compatible with the way it is
being used.  Unfortunately, introducing an additional parentage to an interface
(even though it doesn't affect the available methods) can trigger this
incompatibility check.

Admittedly, there is probably not a lot of code in the world that would be
affected by this in the case of SessionListener -- but it is still a real issue.

--
To unsubscribe, e-mail:   <mailto:tomcat-dev-unsubscribe@jakarta.apache.org>
For additional commands, e-mail: <mailto:tomcat-dev-help@jakarta.apache.org>


Mime
View raw message