What is the use of the Random(long) constructor?

Question

There are 2 constructors of Random class

1. public Random()
2. public Random(long seed)

The description for the second constructor as per oracle states as

Creates a new random number generator using a single long seed. The seed is the initial value of the internal state of the pseudorandom number generator which is maintained by method next(int).

I did not understand it completely. And I did not find any articles/book which clearly explains why,when and how it is used.

Can any one explain please?

Answer 1

If you use the constructor with the seed, you will get a repeatable sequence, so it's good for testing. If you use the constructor without the seed, you don't know what sequence of random-like numbers will be produced.