private long getSeedForRandom() throws InitializationError
    {
        String seed = System.getProperty("jcheck.seed");
        if (seed != null) {
            try {
                return Long.parseLong(seed);
            }
            catch (NumberFormatException ex) {
                throw new InitializationError("The given seed is not a number");
            }
        }
        
        return System.currentTimeMillis();
    }