What is a servlet container?

A servlet container is a component of a web server that manages the lifecycle of servlets (special Java classes that handle HTTP requests). It is responsible for:

• Loading servlets: Dynamically loads servlet classes upon the first request or at startup.
• Initializing servlets: Calls the init() method of the servlet after it is loaded.
• Handling requests: Creates HttpServletRequest and HttpServletResponse objects for each incoming HTTP request and passes them to the appropriate servlet via the service() method.
• Managing threads: Creates and manages threads for concurrent processing of multiple requests.
• Shutting down servlets: Calls the destroy() method of the servlet when the container is shutting down.

Examples of popular servlet containers:

• Apache Tomcat
• Eclipse Jetty
• WildFly (includes the Undertow servlet container)

Essentially, a servlet container provides a runtime environment for web applications based on servlets and JSP technology, abstracting developers from low-level details of HTTP handling and thread management.