/**
     * Default constructor for the GenerateThumbnailJob.
     */
    public GenerateThumbnailJob() {
        super();
    }

    /**
     * Sets the number of threads to use for thumbnail generation.
     *
     * @param numOfThreads the number of threads
     * @return this job instance for method chaining
     */
    public GenerateThumbnailJob numOfThreads(final int numOfThreads) {