Freemarker
Freemarker is a Java-based template engine for generating text output (HTML, XML, emails, configuration files, etc.) based on templates and data models. It separates presentation logic from business logic by allowing developers to embed dynamic content in static templates using a simple syntax. It's widely used in web applications, particularly with Java frameworks, to render dynamic web pages and other text-based formats.
Developers should learn Freemarker when building Java web applications that require server-side rendering of dynamic content, such as with Spring MVC or Apache Struts, as it integrates seamlessly and offers a clean separation of concerns. It's also useful for generating emails, reports, or configuration files where template-based text generation is needed, providing a lightweight and efficient alternative to JSP for many use cases.