I thought this would be easy to achieve, but so far I haven\'t found solutions for comment/uncomment shortcut on both Java class editor and jsf faceted we
For single line comment you can use Ctrl + / and for multiple line comment you can use Ctrl + Shift + / after selecting the lines you want to comment in java editor.
On Mac/OS X you can use ⌘ + / to comment out single lines or selected blocks.