Java Servlets are Java classes that extend the functionality of a web server to handle HTTP requests and responses. Servlets are part of the Java EE (Enterprise Edition) platform and are commonly used to develop dynamic web applications. Servlets run on the server-side and interact with web clients through the request-response model. They receive HTTP requests from clients, process them, and generate HTTP responses to send back to the clients. Servlets are typically deployed within a web container such as Apache Tomcat or Jetty, which manages their lifecycle and provides the necessary infrastructure for handling HTTP requests. Servlets can perform various tasks such as processing form data, accessing databases, and generating dynamic content based on user input or business logic. They offer advantages such as platform independence, scalability, and extensibility, making them a popular choice for building web applications in Java.