How to check the version of JSF

1.
FacesContext.class.getPackage().getImplementationVersion();
FacesContext.class.getPackage().getImplementationVendor();
FacesContext.class.getPackage().getImplementationTitle();

2.
The exact JSF implementation version information is available in /META-INF/MANIFEST.MF file of the JSF implementation JAR file. It's usually located near the bottom of the manifest file as follows:

Implementation-Title: Mojarra
Implementation-Version: 1.2_12-b01-FCS
Implementation-Vendor: Sun Microsystems, Inc.