public static boolean isRosterServiceEnabled() {
        return JiveGlobals.getBooleanProperty("xmpp.client.roster.active", true);
    }
Returns true if the roster service is enabled. When disabled it is not possible to
retrieve users rosters or broadcast presence packets to roster contacts.

@return true if the roster service is enabled.
xmppserver/src/main/java/org/jivesoftware/openfire/roster/RosterManager.java