What are Servlets?
#servlets #nio #web
Servlets API is used for client-server communication, commonly through HTTP. Java Servlets 2.2 became a part of J2EE in 1999, they introduced independent web applications in .war files. API was drastically improved in the 3.0 version and now it's distributed under the Jakarta Servlet API having 5.0 released version.
How do they work?
Servlets are just a convenient abstract layer for async kernel calls that acquire a socket to listen for incoming events. Events can be represented as handshakes over TCP connection.
How to use them?
Servlets need a container that will dispatch commands of the outside world to it. The web container is responsible for managing the lifecycle of servlets, mapping a URL to a particular servlet and ensuring that the URL requester has the correct access rights. Jetty, Netty, Tomcat, etc. can provide implementations for such a container and Spring will provide an embedded instance in runtime of any of them.
wikiwand.com/en/Jakarta_Servlet
