One of the major changes in Tomcat 7 is that it supports the Servlet 3.0 specification. A major part of the Servlet 3.0 specification is obviously the support for asynchronous requests. Some of us need to use Apache and mod_jk to provide load balancing over multiple Tomcats. This means using the AJP connector, which currently has only BIO and APR options. For those of us needing to support many (7) different platforms (some with horrific linkers, etc), APR is just not a workable solution -- too many nasty builds. For such use cases a NIO-based AJP connector would really be enormously helpful. Mark Thomas stated, "I don't know how much work that would be to write but with the refactoring already completed for Tomcat 7 it might be as little as 1000 lines of code."
An initial implementation is available in trunk/7.0.x. It will be included in 7.0.15 onwards. There are some aspects that are known to fail (e.g. request bodies). Once all the TCK tests pass, the experimental label will be removed and this issue will be marked as resolved.
This has been implemented in 7.0.x and will be included in 7.0.15 onwards.
Does it pass TCK tests yet?
Yep. It passes the Servlet 3.0 TCK with mod_jk and mod_proxy_ajp.