Mojarra is Sun's high performance, battle-tested implementation of JSF, and is used in IBM
WebSphere™, Oracle WebLogic™, Oracle 10g Application Server, SpringSource dm Server™, and
other popular enterprise platforms.
Like all of Java, Mojarra is open source, dual licensed with GPL+Classpath Exception and CDDL.
Mojarra was the first JSF runtime to support Groovy, and does so for all of JSF.