Whether a parameter is required or optional determines how a subcommand responds if a user omits the parameter when running the subcommand:
If the parameter is required, the subcommand returns an error.
If the parameter is optional, the subcommand runs successfully.
To specify whether a parameter is optional or required, set the optional element of the @Param annotation as follows:
If the parameter is required, set the optional element to false. This value is the default.
If the parameter is optional, set the optional element to true.