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
Ctrl+/ to toggle "//" comments and Ctrl+Shift/ to toggle "/* */" comments. At least for Java, anyway - other tooling may have different shortcuts.
Ctrl+\ will remove a block of either comment, but won't add comments.
EDIT: It's Ctrl on a PC, but on a Mac the shortcuts may all be Cmd instead. I don't have a Mac myself, so can't easily check