jobExecutor.addShutdownListener(() -> ComponentUtil.getProcessHelper().destroyProcess(sessionId));
        }

        final TimeoutTask timeoutTask = createTimeoutTask();
        try {
            executeThumbnailGenerator();
        } catch (final Exception e) {
            logger.warn("Failed to generate thumbnails.", e);
            resultBuf.append(e.getMessage()).append("\n");
        } finally {