Why is Random() not behaving as expected? [duplicate]

Question

I've been scratching my head over this for long enough, It's time for the big guns:

System.out.println(new Random(10).nextInt());

why does the above seem to print -1157793070, always?

Answer 1

It is because you define a custom seed that is always the same with each run. From the JavaDoc:

The seed is the initial value of the internal state of the pseudorandom number generator which is maintained by method {@link #next}.

This is particularly useful for running tests.