new Random().nextInt(999999) sometimes generates 5 digit number

Question

I am using new Random().nextInt(999999) to generate a 6 digit random number. But sometimes it generates 5 digit numbers. And I explicitly have to check if generated number is not 6 digit.

Why this method does that? And is there any other way to be pretty sure it generate only 6 digit random number.

Answer 1

Random().nextInt(999999) generates number between 0 and 999998, so you have ~10% chance to get number smaller than 100000 (5 and less digits).

Try

100000 + Random().nextInt(900000)

you will get number in range 100000 - 999999

Answer 2

Random().nextInt(999999) generates 5 digits number sometimes, because it generates random values between 0 and 999999.

Use the following snippet for generating random numbers in a range:

Random random = new Random();
minimum + random.nextInt(maximum - minimum + 1);