Unlike other jcmd -verbose arguments, which can be set, or set specifically to true or false:

jcmd PID VM.classes -verbose=false
...does not set verbose to false.


VM.classes is
866 class ClassesDCmd : public DCmdWithParser {
867 protected:
868 DCmdArgument<bool> _verbose;


994 void ClassesDCmd::execute(DCmdSource source, TRAPS) {
995 VM_PrintClasses vmop(output(), _verbose.is_set());
996 VMThread::execute(&vmop);
997 }

_verbose.is_set() is wrong, it could be set, but set to false.

_verbose.value() should be used (see other examples such as StringtableDCmd::execute).