The application server is HTTP 1.1 compliant, and it must support all the features described in
HTTP Made Really Easy. This means that it must be able to support HTTP 1.0 clients as well as 1.1 clients.
Persistent connections are suggested but not required for HTTP 1.1 servers. 

For efficiency, the server is implemented using a thread pool. Specifically, there is one thread that listens for incoming TCP requests and enqueues them, and some number of threads that process the requests from the queue and return the responses. 
Everything is written from scratch including the thread pool and blocking Queue.