141120 Random

/**
     * Creates a new random number generator using a single {@code long} seed.
     * The seed is the initial value of the internal state of the pseudorandom
     * number generator which is maintained by method {@link #next}.
     *
     * <p>The invocation {@code new Random(seed)} is equivalent to:
     *  <pre> {@code
     * Random rnd = new Random();
     * rnd.setSeed(seed);}</pre>
     *
     * @param seed the initial seed
     * @see   #setSeed(long)
     */
    public Random(long seed) {
        this.seed = new AtomicLong(0L);
        setSeed(seed);
    }

/**
     * Returns the next pseudorandom, uniformly distributed {@code int}
     * value from this random number generator‘s sequence. The general
     * contract of {@code nextInt} is that one {@code int} value is
     * pseudorandomly generated and returned. All 2<font size="-1"><sup>32
     * </sup></font> possible {@code int} values are produced with
     * (approximately) equal probability.
     *
     * <p>The method {@code nextInt} is implemented by class {@code Random}
     * as if by:
     *  <pre> {@code
     * public int nextInt() {
     *   return next(32);
     * }}</pre>
     *
     * @return the next pseudorandom, uniformly distributed {@code int}
     *         value from this random number generator‘s sequence
     */
    public int nextInt() {
	return next(32);
    }

141120 Random

原文：http://my.oschina.net/wrean/blog/346651