@Override
    public ServiceTicket grantServiceTicket(
        final String id, final Service service,
        final ExpirationPolicy expirationPolicy,
        final boolean credentialProvided,
        final TicketTrackingPolicy trackingPolicy) {
        val serviceTicket = new ServiceTicketImpl(id, this, service, credentialProvided, expirationPolicy);
        serviceTicket.setTenantId(service.getTenant());
        trackingPolicy.trackTicket(this, serviceTicket);
        return serviceTicket;
    }
The ticket ids which are tied to this ticket.
core/cas-server-core-tickets-api/src/main/java/org/apereo/cas/ticket/TicketGrantingTicketImpl.java