SMailCallbackContext.setPreparedMessageHookOnThread(notificationHelper::send);
                    EsStatusPostcard.droppedInto(postbox, postcard -> {
                        postcard.setFrom(fessConfig.getMailFromAddress(), fessConfig.getMailFromName());
                        postcard.addReplyTo(fessConfig.getMailReturnPath());
                        if (toAddresses.length > 0) {

                SMailCallbackContext.setPreparedMessageHookOnThread(notificationHelper::send);
                CrawlerPostcard.droppedInto(postbox, postcard -> {
                    postcard.setFrom(fessConfig.getMailFromAddress(), fessConfig.getMailFromName());
                    postcard.addReplyTo(fessConfig.getMailReturnPath());
                    if (toAddresses.length > 0) {

        final Postbox postbox = ComponentUtil.getComponent(Postbox.class);
        try {
            TestmailPostcard.droppedInto(postbox, postcard -> {
                postcard.setFrom(fessConfig.getMailFromAddress(), fessConfig.getMailFromName());
                postcard.addReplyTo(fessConfig.getMailReturnPath());
                stream(toAddresses).of(stream -> stream.forEach(address -> {
                    postcard.addTo(address);

     * comment: Email address to use in the From field.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getMailFromAddress();

    /**
     * Get the value for the key 'mail.hostname'. <br>
     * The value is, e.g.  <br>
     * comment: Hostname for the mail server.