Before JSF existed, most Java web applications were typically developed using nonstandard (as in, not part of the Java EE specification) web application frameworks such as Apache Struts, Tapestry, and Spring Web MVC, among others. These frameworks are built on top of the Servlet and JSP standards and automate a lot of functionality that needs to be manually coded when using these APIs directly.
Having a wide variety of web application frameworks available often resulted in analysis paralysis, that is, developers often spent an inordinate amount of time evaluating frameworks for their applications.
The introduction of JSF to the Java EE specification resulted in a standard, very capable web application framework available in any Java EE-compliant application server. With JSF being the standard Java EE framework, nowadays many Java enterprise application developers choose to use JSF to develop their user interface.
