@Override
    public List<JID> getAdmins() {
        // Add bare JIDs of users that are admins (may include remote users), primarily used to override/add to list of admin users
        final List<JID> adminList = ADMIN_JIDS.getValue();

        // Prior to 4.4.0, the return value was mutable. To prevent issues, we'll keep that characteristic.
        final List<JID> returnValue = new ArrayList<>();

        if (adminList.isEmpty()) {
            // Add default admin account when none was specified
            returnValue.add( new JID("admin", XMPPServer.getInstance().getServerInfo().getXMPPDomain(), null, true));
        } else {
            returnValue.addAll( adminList );
        }

        return returnValue;
    }
The default provider retrieves the comma separated list from the system property
{@code admin.authorizedJIDs}
@see org.jivesoftware.openfire.admin.AdminProvider#getAdmins()
xmppserver/src/main/java/org/jivesoftware/openfire/admin/DefaultAdminProvider.java