default void setPasswordRequiredForSysadminsToJoinRoom(boolean isRequired) {
        MUCPersistenceManager.setProperty( getServiceName(), "sysadmin.requires.room.passwords", Boolean.toString(isRequired) );
    }
Sets if a system administrator of the MUC service can join a
password-protected room, without supplying the password.

@param isRequired false if a sysadmin is allowed to join a password-protected room without a password, otherwise true.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/MultiUserChatService.java