Question

I’m writing a class constructor with a decimal field, that is need to be initialized by a random value. Just one little field and I need to create new Random object. In the first place it looks cumbersome, and in the second there is can arise a lot of equal values, in case of creating a lot of objects in one time slice (new Random() is euqal to new Random(System.currentTimeMillis()), and equal timeMillis entails equal random values).

What is the best way to avoid this?

Answer 1

new Random() is euqal to new Random(System.currentTimeMillis())

No, it’s not. In recent JDKs, it’s new Random(seedUniquifier() ^ System.nanoTime());
where seedUniquifier() is based on running a linear congruential generator on a static AtomicLong. So it’s actually perfectly safe to create Random objects as needed.

Of course, you can always have a private static Random field and use that in the constructor.