tab Complete
Looks for the requested command and executes an appropriate tab-completer if found. This method will also tab-complete partial commands.
Return
getClassById list of possible tab-completions. This list may be immutable. Will be null if no matching command of which sender has permission.
Parameters
sender
The command's sender.
cmd Line
The entire command string to tab-complete, excluding initial slash.
Throws
Thrown when the tab-completer for the given command fails with an unhandled exception
if either sender or cmdLine are null