Jakarta Server Faces is a Java specification for building component-based user interfaces for web applications and was formalized as a standard through the Java Community Process being part of the Java Platform, Enterprise Edition. It is also a MVCweb framework that simplifies construction of user interfaces for server-based applications by using reusable UI components in a page. JSF 2 uses Facelets as its default templating system. Other view technologies such as XUL or plain Java can also be employed. In contrast, JSF 1.x uses JavaServer Pages as its default templating system.
History
In 2001, the original Java Specification Request for the technology that ultimately became JavaServer Faces proposed developing a package with the name javax.servlet.ui By June 2001, JavaWorld would report on Amy Fowler's team's design of "the JavaServer Faces API" – "an application framework for creating Web-based user interfaces".
Versions
JSF 2.3 – Major features: search Expressions, extensionless URLs, bean validation for complete classes, push communication using WebSocket, enhanced integration with CDI.
JSF 2.2 – Introduced new concepts like stateless views, page flow and the ability to create portable resource contracts.
JSF 2.1 – Maintenance release 2 of JSF 2.0. Only a very minor number of specification changes.
JSF 2.0 – Major release for ease of use, enhanced functionality, and performance. Coincides with Java EE 6.
JSF 1.2 – Many improvements to core systems and APIs. Coincides with Java EE 5. Initial adoption into Java EE.
JSF 1.1 – Bug-fix release. No specification changes.
JSF 1.0 – Initial specification released.
How it works
Based on a component-driven UI design-model, JavaServer Faces uses XML files called view templates or Facelets views. The FacesServlet processes requests, loads the appropriate view template, builds a component tree, processes events, and renders the response to the client. The state of UI components and other objects of scope interest is saved at the end of each request in a process called stateSaving, and restored upon next creation of that view. Either the client or the server side can save objects and states.
JSF is often used together with Ajax, a Rich Internet application development technique. Ajax is a combination of web development techniques and technologies that make it possible to create rich user interfaces. The user interface components in Mojarra and Apache MyFaces were originally developed for HTML only, and Ajax had to be added via JavaScript. This has changed, however: Because JSF supports multiple output formats, Ajax-enabled components can easily be added to enrich JSF-based user interfaces. The JSF 2.0 specification provides built-in support for Ajax by standardizing the Ajax request lifecycle and providing simple development interfaces to Ajax events, allowing any event triggered by the client to go through proper validation, conversion, and finally method invocation, before returning the result to the browser via an XML DOM update. JSF 2 includes support for graceful degradation when JavaScript is disabled in the browser.
Ajax-enabled components and frameworks
The following companies and projects offer Ajax-based JSF frameworks or component libraries:
Apache MyFaces – The Apache Foundation JSF implementation with Ajax components
was adopted as the official view technology for JSF 2.0. This eliminates the life-cycle conflicts that existed with JSP, forcing workarounds by Java developers. Facelets allows easy component/tag creation using XML markup instead of Java code, the chief complaint against JSF 1.x. The new JSF developments also provide wide accessibility to Java 5 annotations such as @ManagedBean, @ManagedProperty and @FacesComponent that removes the need for faces-config.xml in all cases except framework extension. Navigation has been simplified, removing the need for faces-config.xml navigation cases. Page transitions can be invoked simply by passing the name of the desired View/Facelet. Addition of Partial State Saving and DOM updates are part of the built-in standardized Ajax support. The latest JSF release has built-in support for handling resources like images, CSS and Javascript, allowing artifacts to be included with component libraries, separated into JAR files, or simply co-located into a consistent place within the Web application. This includes logical naming and versioning of resources. JSF 2.0 also includes a number of other changes like adding support for events, separate development, staging, and production modes, similar to RAILS_ENV in Ruby on Rails, and significantly expanding the standard set of components.
Criticisms
In their January 2014 "Technology Radar" publication, ThoughtWorks wrote: In the article published November 2014 in the DZone website, titled "Why You Should Avoid JSF", Jens Schauder wrote:
Rebuttal to criticisms
In February 2014, Çağatay Çivici responded to ThoughtWorks criticisms in a post titled: JSF is not what you’ve been told anymore. Çivici argues that improvements in JSF over the years offer many features that embrace modern web development, providing the option to write your own JavaScript, HTML, and CSS. Also regarding state, Çağatay wrote:
